diff --git a/.dockerignore b/.dockerignore
new file mode 100644
index 0000000..e052dcf
--- /dev/null
+++ b/.dockerignore
@@ -0,0 +1 @@
+builder/build
diff --git a/.gitignore b/.gitignore
index 63463c4..ccb6180 100644
--- a/.gitignore
+++ b/.gitignore
@@ -14,3 +14,10 @@ config.h
 
 builder/build/
 builder/www/
+
+# Deb building artefacts
+debian/.debhelper/
+debian/files
+debian/kasmvncserver.substvars
+debian/kasmvncserver/
+.pc
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 90eadc1..c72a155 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -18,8 +18,7 @@ build:
     - bash builder/build-tarball
     - bash builder/build-deb
     - mkdir output
-    - cp builder/build/kasmvncserver_*.deb output/
-    - cp builder/build/kasmvnc.*.tar.gz output/
+    - cp -r builder/build/* output/
   artifacts:
     paths:
       - output/
diff --git a/LICENCE.TXT b/LICENCE.TXT
index ae3b531..d159169 100644
--- a/LICENCE.TXT
+++ b/LICENCE.TXT
@@ -1,12 +1,12 @@
-		    GNU GENERAL PUBLIC LICENSE
-		       Version 2, June 1991
+                    GNU GENERAL PUBLIC LICENSE
+                       Version 2, June 1991
 
-	  Copyright (C) 1989, 1991 Free Software Foundation, Inc.
-	 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA
+ Copyright (C) 1989, 1991 Free Software Foundation, Inc.,
+ 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  Everyone is permitted to copy and distribute verbatim copies
  of this license document, but changing it is not allowed.
 
-			    Preamble
+                            Preamble
 
   The licenses for most software are designed to take away your
 freedom to share and change it.  By contrast, the GNU General Public
@@ -15,7 +15,7 @@ software--to make sure the software is free for all its users.  This
 General Public License applies to most of the Free Software
 Foundation's software and to any other program whose authors commit to
 using it.  (Some other Free Software Foundation software is covered by
-the GNU Library General Public License instead.)  You can apply it to
+the GNU Lesser General Public License instead.)  You can apply it to
 your programs, too.
 
   When we speak of free software, we are referring to freedom, not
@@ -55,8 +55,8 @@ patent must be licensed for everyone's free use or not licensed at all.
 
   The precise terms and conditions for copying, distribution and
 modification follow.
-
-		    GNU GENERAL PUBLIC LICENSE
+
+                    GNU GENERAL PUBLIC LICENSE
    TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
 
   0. This License applies to any program or other work which contains
@@ -110,7 +110,7 @@ above, provided that you also meet all of these conditions:
     License.  (Exception: if the Program itself is interactive but
     does not normally print such an announcement, your work based on
     the Program is not required to print an announcement.)
-
+
 These requirements apply to the modified work as a whole.  If
 identifiable sections of that work are not derived from the Program,
 and can be reasonably considered independent and separate works in
@@ -168,7 +168,7 @@ access to copy from a designated place, then offering equivalent
 access to copy the source code from the same place counts as
 distribution of the source code, even though third parties are not
 compelled to copy the source along with the object code.
-
+
   4. You may not copy, modify, sublicense, or distribute the Program
 except as expressly provided under this License.  Any attempt
 otherwise to copy, modify, sublicense or distribute the Program is
@@ -225,7 +225,7 @@ impose that choice.
 
 This section is intended to make thoroughly clear what is believed to
 be a consequence of the rest of this License.
-
+
   8. If the distribution and/or use of the Program is restricted in
 certain countries either by patents or by copyrighted interfaces, the
 original copyright holder who places the Program under this License
@@ -255,7 +255,7 @@ make exceptions for this.  Our decision will be guided by the two goals
 of preserving the free status of all derivatives of our free software and
 of promoting the sharing and reuse of software generally.
 
-			    NO WARRANTY
+                            NO WARRANTY
 
   11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
 FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW.  EXCEPT WHEN
@@ -277,9 +277,9 @@ YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER
 PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE
 POSSIBILITY OF SUCH DAMAGES.
 
-		     END OF TERMS AND CONDITIONS
-
-	Appendix: How to Apply These Terms to Your New Programs
+                     END OF TERMS AND CONDITIONS
+
+            How to Apply These Terms to Your New Programs
 
   If you develop a new program, and you want it to be of the greatest
 possible use to the public, the best way to achieve this is to make it
@@ -291,7 +291,7 @@ convey the exclusion of warranty; and each file should have at least
 the "copyright" line and a pointer to where the full notice is found.
 
     <one line to give the program's name and a brief idea of what it does.>
-    Copyright (C) 19yy  <name of author>
+    Copyright (C) <year>  <name of author>
 
     This program is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -303,17 +303,16 @@ the "copyright" line and a pointer to where the full notice is found.
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     GNU General Public License for more details.
 
-    You should have received a copy of the GNU General Public License
-    along with this program; if not, write to the Free Software
-    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307,
-    USA.
+    You should have received a copy of the GNU General Public License along
+    with this program; if not, write to the Free Software Foundation, Inc.,
+    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 
 Also add information on how to contact you by electronic and paper mail.
 
 If the program is interactive, make it output a short notice like this
 when it starts in an interactive mode:
 
-    Gnomovision version 69, Copyright (C) 19yy name of author
+    Gnomovision version 69, Copyright (C) year name of author
     Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
     This is free software, and you are welcome to redistribute it
     under certain conditions; type `show c' for details.
@@ -336,5 +335,5 @@ necessary.  Here is a sample; alter the names:
 This General Public License does not permit incorporating your program into
 proprietary programs.  If your program is a subroutine library, you may
 consider it more useful to permit linking proprietary applications with the
-library.  If this is what you want to do, use the GNU Library General
+library.  If this is what you want to do, use the GNU Lesser General
 Public License instead of this License.
diff --git a/builder/build-deb b/builder/build-deb
index d068f8e..73751ef 100755
--- a/builder/build-deb
+++ b/builder/build-deb
@@ -3,11 +3,14 @@
 set -e
 
 cd "$(dirname "$0")/.."
+. builder/os_ver_cli.sh
 
-docker build -t debbuilder_ubuntu:18.04 -f \
-  builder/dockerfile.ubuntu1804.deb.build .
+docker build -t debbuilder_${os}:${os_codename} -f \
+  builder/dockerfile.${os}_${os_codename}.deb.build .
 
 deb_output_dir=$(cd .. && echo $PWD)
 L_UID=$(id -u) #Ubuntu already has UID env var, but this should work on all Linix systems
 L_GID=$(id -g)
-docker run --rm -v "$deb_output_dir":/src --user $L_UID:$L_GID debbuilder_ubuntu:18.04 /bin/bash -c '/src/*/builder/build-deb-inside-docker'
+docker run --rm -v "$deb_output_dir":/src --user $L_UID:$L_GID \
+  debbuilder_${os}:${os_codename} /bin/bash -c \
+  '/src/*/builder/build-deb-inside-docker'
diff --git a/builder/build-deb-inside-docker b/builder/build-deb-inside-docker
index 43c4e3a..faca5d0 100755
--- a/builder/build-deb-inside-docker
+++ b/builder/build-deb-inside-docker
@@ -4,6 +4,11 @@ set -e
 
 cd "$(dirname "$0")/.."
 
+os=$(lsb_release -is | tr '[:upper:]' '[:lower:]')
+os_codename=$(lsb_release -cs)
+os_dir="builder/build/${os_codename}"
+
 dpkg-buildpackage -us -uc -b
-cp ../*.deb builder/build
+mkdir -p "$os_dir"
+cp ../*.deb "$os_dir"
 lintian ../*.deb || true
diff --git a/builder/build-rpm b/builder/build-rpm
new file mode 100755
index 0000000..39724d5
--- /dev/null
+++ b/builder/build-rpm
@@ -0,0 +1,16 @@
+#!/bin/bash
+
+set -e
+
+cd "$(dirname "$0")/.."
+. builder/os_ver_cli.sh
+
+docker build -t kasmvnc_rpmbuilder_${os}:${os_codename} -f \
+  builder/dockerfile.${os}_${os_codename}.rpm.build .
+
+source_dir=$(echo $PWD)
+L_UID=$(id -u) #Ubuntu already has UID env var, but this should work on all Linix systems
+L_GID=$(id -g)
+docker run --rm -v "$source_dir":/src --user $L_UID:$L_GID \
+  kasmvnc_rpmbuilder_${os}:${os_codename} /bin/bash -c \
+  '/src/builder/build-rpm-inside-docker'
diff --git a/builder/build-rpm-inside-docker b/builder/build-rpm-inside-docker
new file mode 100755
index 0000000..5f51cd1
--- /dev/null
+++ b/builder/build-rpm-inside-docker
@@ -0,0 +1,30 @@
+#!/bin/bash
+
+set -e
+
+prepare_build_env() {
+  rpmdev-setuptree
+  copy_spec_and_tar_with_binaries
+}
+
+copy_spec_and_tar_with_binaries() {
+  cp /src/centos/kasmvncserver.spec ~/rpmbuild/SPECS/
+  cp /src/builder/build/kasmvnc.${os}_${os_codename}.tar.gz \
+    ~/rpmbuild/SOURCES/
+}
+
+copy_rpm_to_build_dir() {
+  cd /src/builder && \
+    mkdir -p "$os_dir" && cp ~/rpmbuild/RPMS/*/*.rpm ${os_dir}
+}
+
+cd "$(dirname "$0")/.."
+
+os=$(lsb_release -is | tr '[:upper:]' '[:lower:]')
+os_codename=$(lsb_release -cs | tr '[:upper:]' '[:lower:]')
+os_dir="build/${os}_${os_codename}"
+
+prepare_build_env
+rpmbuild -ba ~/rpmbuild/SPECS/kasmvncserver.spec
+copy_rpm_to_build_dir
+rpmlint "$os_dir"/*.rpm || true
diff --git a/builder/build-tarball b/builder/build-tarball
index ec85a4b..a070eaa 100755
--- a/builder/build-tarball
+++ b/builder/build-tarball
@@ -10,15 +10,17 @@ build_www_dir() {
 shared_with_docker_dir=${GITLAB_SHARED_DIND_DIR:-/tmp}
 
 cd "$(dirname "$0")/.."
+. builder/os_ver_cli.sh
 
 build_www_dir
 
-docker pull ubuntu:18.04
-docker build -t kasmvncbuilder:18.04 -f builder/dockerfile.ubuntu1804.build .
+docker build -t kasmvncbuilder:$os_codename \
+  -f builder/dockerfile.${os}_${os_codename}.build .
 mkdir -p builder/build
-docker run -v $shared_with_docker_dir:/build --rm kasmvncbuilder:18.04
+docker run -v $shared_with_docker_dir:/build --rm kasmvncbuilder:$os_codename
 
 L_GID=$(id -g)
 L_UID=$(id -u)
-chown $L_UID:$L_GID $shared_with_docker_dir/kasmvnc.ubuntu_18.04.tar.gz
-mv $shared_with_docker_dir/kasmvnc.ubuntu_18.04.tar.gz $PWD/builder/build/
+tarball_name="kasmvnc.${os}_${os_codename}.tar.gz"
+chown $L_UID:$L_GID $shared_with_docker_dir/$tarball_name
+mv $shared_with_docker_dir/$tarball_name $PWD/builder/build/
diff --git a/builder/build.sh b/builder/build.sh
index 63be78d..73a7b34 100755
--- a/builder/build.sh
+++ b/builder/build.sh
@@ -1,5 +1,12 @@
 #!/bin/sh -e
 
+detect_quilt() {
+  if which quilt 1>/dev/null; then
+    QUILT_PRESENT=1
+    export QUILT_PATCHES=debian/patches
+  fi
+}
+
 # For build-dep to work, the apt sources need to have the source server
 #sudo apt-get build-dep xorg-server
 
@@ -23,7 +30,7 @@ sed -i -e '/find_package(FLTK/s@^@#@' \
 	-e '/add_subdirectory(tests/s@^@#@' \
 	CMakeLists.txt
 
-cmake .
+cmake -D CMAKE_BUILD_TYPE=RelWithDebInfo .
 make -j5
 
 tar -C unix/xserver -xvf /tmp/xorg-server-${XORG_VER}.tar.bz2 --strip-components=1
@@ -59,12 +66,17 @@ touch man/man1/Xserver.1
 touch man/man1/Xvnc.1
 mkdir lib
 cd lib
-ln -s /usr/lib/x86_64-linux-gnu/dri dri
+if [ -d /usr/lib/x86_64-linux-gnu/dri ]; then
+  ln -s /usr/lib/x86_64-linux-gnu/dri dri
+else
+  ln -s /usr/lib64/dri dri
+fi
 cd /src
-sed  $'s#pushd $TMPDIR/inst#CWD=$(pwd)\\\ncd $TMPDIR/inst#' release/maketarball > release/maketarball2
-sed  $'s#popd#cd $CWD#' release/maketarball2 > release/maketarball3
-mv release/maketarball3 release/maketarball
 
+detect_quilt
+if [ -n "$QUILT_PRESENT" ]; then
+  quilt push -a
+fi
 make servertarball
 
-cp kasmvnc*.tar.gz /build/kasmvnc.${KASMVNC_BUILD_OS}_${KASMVNC_BUILD_OS_VER}.tar.gz
+cp kasmvnc*.tar.gz /build/kasmvnc.${KASMVNC_BUILD_OS}_${KASMVNC_BUILD_OS_CODENAME}.tar.gz
diff --git a/builder/dockerfile.centos7.build b/builder/dockerfile.centos7.build
deleted file mode 100644
index 288db42..0000000
--- a/builder/dockerfile.centos7.build
+++ /dev/null
@@ -1,20 +0,0 @@
-FROM centos:centos7
-
-RUN yum install -y build-dep xorg-server libxfont-dev sudo
-RUN yum install -y cmake git libjpeg-dev libgnutls28-dev vim wget tightvncserver
-RUN yum install -y libjpeg-dev libpng-dev libtiff-dev libgif-dev libavcodec-dev libssl-dev
-
-# Additions for webp
-RUN cd /tmp && wget https://storage.googleapis.com/downloads.webmproject.org/releases/webp/libwebp-1.0.2.tar.gz
-RUN cd /tmp && tar -xzvf /tmp/libwebp-*
-RUN cd /tmp/libwebp-1.0.2 && \
-    ./configure --enable-static --disable-shared && \
-    make && make install
-
-RUN useradd -m docker && echo "docker:docker" | chpasswd && adduser docker sudo
-
-COPY . /src
-RUN chown -R docker:docker /src
-
-USER docker
-ENTRYPOINT ["/src/builder/build.sh"]
diff --git a/builder/dockerfile.centos_core.barebones.rpm.test b/builder/dockerfile.centos_core.barebones.rpm.test
new file mode 100644
index 0000000..3852d29
--- /dev/null
+++ b/builder/dockerfile.centos_core.barebones.rpm.test
@@ -0,0 +1,20 @@
+FROM centos:centos7
+
+RUN yum install -y epel-release && yum install -y openbox xterm
+RUN yum erase -y pm-utils xscreensaver*
+RUN yum install -y vim less
+
+ARG KASMVNC_PACKAGE_DIR
+COPY $KASMVNC_PACKAGE_DIR/*.rpm /tmp
+RUN yum localinstall -y /tmp/*.rpm
+
+RUN useradd -m foo
+
+USER foo:kasmvnc
+
+RUN mkdir -p ~/.config/openbox && echo xterm > ~/.config/openbox/autostart && chmod +x ~/.config/openbox/autostart
+RUN mkdir ~/.vnc && echo '/usr/bin/openbox-session &' >> ~/.vnc/xstartup && \
+  chmod +x ~/.vnc/xstartup
+RUN echo bar | kasmvncpasswd -f > $HOME/.kasmpasswd && chmod 0600 $HOME/.kasmpasswd
+
+ENTRYPOINT bash -c "vncserver :1 -interface 0.0.0.0 && vncserver -kill :1 && vncserver :1 -depth 24 -geometry 1280x1050 -websocketPort 8443 -cert /etc/pki/tls/private/kasmvnc.pem -sslOnly -FrameRate=24 -interface 0.0.0.0 -httpd /usr/share/kasmvnc/www && tail -f $HOME/.vnc/*.log "
diff --git a/builder/dockerfile.centos_core.build b/builder/dockerfile.centos_core.build
new file mode 100644
index 0000000..06dad21
--- /dev/null
+++ b/builder/dockerfile.centos_core.build
@@ -0,0 +1,29 @@
+FROM centos:centos7
+
+ENV KASMVNC_BUILD_OS centos
+ENV KASMVNC_BUILD_OS_CODENAME core
+
+RUN yum install -y build-dep xorg-server libxfont-dev sudo
+RUN yum install -y gcc cmake git libjpeg-dev libgnutls28-dev vim wget tightvncserver
+RUN yum install -y libjpeg-dev libpng-dev libtiff-dev libgif-dev libavcodec-dev openssl-devel
+RUN yum install -y make
+RUN yum group install -y "Development Tools"
+RUN yum install -y xorg-x11-server-devel zlib-devel libjpeg-turbo-devel
+RUN yum install -y libxkbfile-devel libXfont2-devel xorg-x11-font-utils \
+  xorg-x11-xtrans-devel xorg-x11-xkb-utils-devel
+RUN yum install -y mesa-dri-drivers
+
+# Additions for webp
+RUN cd /tmp && wget https://storage.googleapis.com/downloads.webmproject.org/releases/webp/libwebp-1.0.2.tar.gz
+RUN cd /tmp && tar -xzvf /tmp/libwebp-*
+RUN cd /tmp/libwebp-1.0.2 && \
+    ./configure --enable-static --disable-shared && \
+    make && make install
+
+RUN useradd -m docker && echo "docker:docker" | chpasswd
+
+COPY . /src
+RUN chown -R docker:docker /src
+
+USER docker
+ENTRYPOINT ["/src/builder/build.sh"]
diff --git a/builder/dockerfile.centos_core.rpm.build b/builder/dockerfile.centos_core.rpm.build
new file mode 100644
index 0000000..7a4e208
--- /dev/null
+++ b/builder/dockerfile.centos_core.rpm.build
@@ -0,0 +1,12 @@
+FROM centos:centos7
+
+RUN yum install -y rpm* gpg* rng-tools rpmlint
+RUN yum install -y tree vim less
+RUN yum install -y redhat-lsb-core
+
+COPY centos/*.spec /tmp
+RUN yum-builddep -y /tmp/*.spec
+
+RUN useradd -m docker && echo "docker:docker" | chpasswd
+
+USER docker
diff --git a/builder/dockerfile.centos_core.rpm.test b/builder/dockerfile.centos_core.rpm.test
new file mode 100644
index 0000000..ec02208
--- /dev/null
+++ b/builder/dockerfile.centos_core.rpm.test
@@ -0,0 +1,61 @@
+FROM centos:centos7
+
+ENV DISPLAY=:1 \
+    VNC_PORT=8443 \
+    VNC_RESOLUTION=1280x720 \
+    MAX_FRAME_RATE=24 \
+    VNCOPTIONS="-PreferBandwidth -DynamicQualityMin=4 -DynamicQualityMax=7" \
+    HOME=/home/user \
+    TERM=xterm \
+    STARTUPDIR=/dockerstartup \
+    INST_SCRIPTS=/dockerstartup/install \
+    KASM_RX_HOME=/dockerstartup/kasmrx \
+    DEBIAN_FRONTEND=noninteractive \
+    VNC_COL_DEPTH=24 \
+    VNC_RESOLUTION=1280x1024 \
+    VNC_PW=vncpassword \
+    VNC_USER=user \
+    VNC_VIEW_ONLY_PW=vncviewonlypassword \
+    LD_LIBRARY_PATH=/usr/local/lib/ \
+    OMP_WAIT_POLICY=PASSIVE \
+    SHELL=/bin/bash \
+    SINGLE_APPLICATION=0 \
+    KASMVNC_BUILD_OS=centos \
+    KASMVNC_BUILD_OS_CODENAME=core
+
+EXPOSE $VNC_PORT
+
+WORKDIR $HOME
+
+### REQUIRED STUFF ###
+
+RUN yum install -y openssl xterm gettext wget
+RUN yum install -y centos-release-scl-rh && yum install -y nss_wrapper
+RUN yum install -y xorg-x11-server xorg-x11-xauth xorg-x11-xkb-utils \
+  xkeyboard-config xorg-x11-server-utils
+RUN yum install -y epel-release && yum groupinstall xfce -y
+RUN yum erase -y pm-utils xscreensaver*
+RUN yum install -y redhat-lsb-core
+RUN yum install -y vim less
+
+RUN echo 'source $STARTUPDIR/generate_container_user' >> $HOME/.bashrc
+
+RUN mkdir -p $STARTUPDIR
+COPY startup/ $STARTUPDIR
+
+### START CUSTOM STUFF ####
+
+ARG KASMVNC_PACKAGE_DIR
+COPY $KASMVNC_PACKAGE_DIR/*.rpm /tmp
+RUN yum localinstall -y /tmp/*.rpm
+
+### END CUSTOM STUFF ###
+
+RUN chown -R 1000:0 $HOME
+USER 1000:kasmvnc
+WORKDIR $HOME
+
+RUN mkdir ~/.vnc && echo '/usr/bin/xfce4-session &' >> ~/.vnc/xstartup && \
+  chmod +x ~/.vnc/xstartup
+
+ENTRYPOINT [ "/dockerstartup/vnc_startup.sh" ]
diff --git a/builder/dockerfile.debian_bullseye.build b/builder/dockerfile.debian_bullseye.build
new file mode 100644
index 0000000..3c19f4c
--- /dev/null
+++ b/builder/dockerfile.debian_bullseye.build
@@ -0,0 +1,31 @@
+FROM debian:bullseye-slim
+
+ENV KASMVNC_BUILD_OS debian
+ENV KASMVNC_BUILD_OS_CODENAME bullseye
+ENV XORG_VER 1.20.10
+ENV DEBIAN_FRONTEND noninteractive
+
+RUN grep '^deb'  /etc/apt/sources.list | sed 's#^deb#deb-src#' >> /etc/apt/sources.list
+
+RUN apt-get update && \
+      apt-get -y install sudo
+
+RUN DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends tzdata
+RUN apt-get update && apt-get -y build-dep xorg-server libxfont-dev
+RUN apt-get update && apt-get -y install cmake git libjpeg-dev libgnutls28-dev vim wget tightvncserver
+RUN apt-get update && apt-get -y install libjpeg-dev libpng-dev libtiff-dev libgif-dev libavcodec-dev libssl-dev
+
+# Additions for webp
+RUN cd /tmp && wget https://storage.googleapis.com/downloads.webmproject.org/releases/webp/libwebp-1.0.2.tar.gz
+RUN cd /tmp && tar -xzvf /tmp/libwebp-*
+RUN cd /tmp/libwebp-1.0.2 && \
+    ./configure --enable-static --disable-shared && \
+    make && make install
+
+RUN useradd -m docker && echo "docker:docker" | chpasswd && adduser docker sudo
+
+COPY . /src
+RUN chown -R docker:docker /src
+
+USER docker
+ENTRYPOINT ["/src/builder/build.sh"]
diff --git a/builder/dockerfile.debian_bullseye.deb.build b/builder/dockerfile.debian_bullseye.deb.build
new file mode 100644
index 0000000..7cc3b16
--- /dev/null
+++ b/builder/dockerfile.debian_bullseye.deb.build
@@ -0,0 +1,12 @@
+FROM debian:bullseye
+
+ENV DEBIAN_FRONTEND noninteractive
+
+RUN apt-get update && \
+      apt-get -y install vim build-essential devscripts equivs
+
+# Install build-deps for the package.
+COPY ./debian/control /tmp
+RUN echo YYY | mk-build-deps --install --remove /tmp/control
+
+USER 1000
diff --git a/builder/dockerfile.debian_bullseye.deb.test b/builder/dockerfile.debian_bullseye.deb.test
new file mode 100644
index 0000000..5749f4e
--- /dev/null
+++ b/builder/dockerfile.debian_bullseye.deb.test
@@ -0,0 +1,53 @@
+FROM debian:bullseye-slim
+
+ENV DISPLAY=:1 \
+    VNC_PORT=8443 \
+    VNC_RESOLUTION=1280x720 \
+    MAX_FRAME_RATE=24 \
+    VNCOPTIONS="-PreferBandwidth -DynamicQualityMin=4 -DynamicQualityMax=7" \
+    HOME=/home/user \
+    TERM=xterm \
+    STARTUPDIR=/dockerstartup \
+    INST_SCRIPTS=/dockerstartup/install \
+    KASM_RX_HOME=/dockerstartup/kasmrx \
+    DEBIAN_FRONTEND=noninteractive \
+    VNC_COL_DEPTH=24 \
+    VNC_RESOLUTION=1280x1024 \
+    VNC_PW=vncpassword \
+    VNC_USER=user \
+    VNC_VIEW_ONLY_PW=vncviewonlypassword \
+    LD_LIBRARY_PATH=/usr/local/lib/ \
+    OMP_WAIT_POLICY=PASSIVE \
+    SHELL=/bin/bash \
+    SINGLE_APPLICATION=0 \
+    KASMVNC_BUILD_OS=debian \
+    KASMVNC_BUILD_OS_CODENAME=buster
+
+EXPOSE $VNC_PORT
+
+WORKDIR $HOME
+
+### REQUIRED STUFF ###
+
+RUN apt-get update && apt-get install -y supervisor xfce4 xfce4-terminal xterm libnss-wrapper gettext wget
+RUN apt-get purge -y pm-utils xscreensaver*
+RUN apt-get update && apt-get install -y vim less
+
+RUN echo 'source $STARTUPDIR/generate_container_user' >> $HOME/.bashrc
+
+RUN mkdir -p $STARTUPDIR
+COPY startup/ $STARTUPDIR
+
+### START CUSTOM STUFF ####
+
+ARG KASMVNC_PACKAGE_DIR
+COPY $KASMVNC_PACKAGE_DIR/kasmvncserver_*.deb /tmp
+RUN dpkg -i /tmp/*.deb; apt-get -yf install
+
+### END CUSTOM STUFF ###
+
+RUN chown -R 1000:0 $HOME
+USER 1000:ssl-cert
+WORKDIR $HOME
+
+ENTRYPOINT [ "/dockerstartup/vnc_startup.sh" ]
diff --git a/builder/dockerfile.debian_buster.barebones.deb.test b/builder/dockerfile.debian_buster.barebones.deb.test
new file mode 100644
index 0000000..f219d8b
--- /dev/null
+++ b/builder/dockerfile.debian_buster.barebones.deb.test
@@ -0,0 +1,12 @@
+FROM debian:buster-slim
+
+ARG KASMVNC_PACKAGE_DIR
+COPY $KASMVNC_PACKAGE_DIR/kasmvncserver_*.deb /tmp
+RUN apt-get update && dpkg -i /tmp/*.deb; apt-get -yf install
+RUN apt-get update && apt-get -y install x11-xserver-utils xterm twm
+
+RUN useradd -m docker && addgroup docker ssl-cert
+
+USER docker
+
+ENTRYPOINT bash -c "vncserver :1 -interface 0.0.0.0 && vncserver -kill :1 && vncserver :1 -depth 24 -geometry 1280x1050 -websocketPort 8443 -cert /etc/ssl/certs/ssl-cert-snakeoil.pem -key /etc/ssl/private/ssl-cert-snakeoil.key -sslOnly -FrameRate=24 -interface 0.0.0.0 -httpd /usr/share/kasmvnc/www && tail -f $HOME/.vnc/*.log "
diff --git a/builder/dockerfile.debian10.build b/builder/dockerfile.debian_buster.build
similarity index 96%
rename from builder/dockerfile.debian10.build
rename to builder/dockerfile.debian_buster.build
index 99cfd10..721b1a6 100644
--- a/builder/dockerfile.debian10.build
+++ b/builder/dockerfile.debian_buster.build
@@ -1,7 +1,7 @@
 FROM debian:buster
 
 ENV KASMVNC_BUILD_OS debian
-ENV KASMVNC_BUILD_OS_VER 10
+ENV KASMVNC_BUILD_OS_CODENAME buster
 ENV XORG_VER 1.20.10
 ENV DEBIAN_FRONTEND noninteractive
 
diff --git a/builder/dockerfile.debian_buster.deb.build b/builder/dockerfile.debian_buster.deb.build
new file mode 100644
index 0000000..d3d4e9b
--- /dev/null
+++ b/builder/dockerfile.debian_buster.deb.build
@@ -0,0 +1,12 @@
+FROM debian:buster
+
+ENV DEBIAN_FRONTEND noninteractive
+
+RUN apt-get update && \
+      apt-get -y install vim build-essential devscripts equivs
+
+# Install build-deps for the package.
+COPY ./debian/control /tmp
+RUN echo YYY | mk-build-deps --install --remove /tmp/control
+
+USER 1000
diff --git a/builder/dockerfile.debian_buster.deb.test b/builder/dockerfile.debian_buster.deb.test
new file mode 100644
index 0000000..53d6b5d
--- /dev/null
+++ b/builder/dockerfile.debian_buster.deb.test
@@ -0,0 +1,53 @@
+FROM debian:buster-slim
+
+ENV DISPLAY=:1 \
+    VNC_PORT=8443 \
+    VNC_RESOLUTION=1280x720 \
+    MAX_FRAME_RATE=24 \
+    VNCOPTIONS="-PreferBandwidth -DynamicQualityMin=4 -DynamicQualityMax=7" \
+    HOME=/home/user \
+    TERM=xterm \
+    STARTUPDIR=/dockerstartup \
+    INST_SCRIPTS=/dockerstartup/install \
+    KASM_RX_HOME=/dockerstartup/kasmrx \
+    DEBIAN_FRONTEND=noninteractive \
+    VNC_COL_DEPTH=24 \
+    VNC_RESOLUTION=1280x1024 \
+    VNC_PW=vncpassword \
+    VNC_USER=user \
+    VNC_VIEW_ONLY_PW=vncviewonlypassword \
+    LD_LIBRARY_PATH=/usr/local/lib/ \
+    OMP_WAIT_POLICY=PASSIVE \
+    SHELL=/bin/bash \
+    SINGLE_APPLICATION=0 \
+    KASMVNC_BUILD_OS=debian \
+    KASMVNC_BUILD_OS_CODENAME=buster
+
+EXPOSE $VNC_PORT
+
+WORKDIR $HOME
+
+### REQUIRED STUFF ###
+
+RUN apt-get update && apt-get install -y supervisor xfce4 xfce4-terminal xterm libnss-wrapper gettext wget
+RUN apt-get purge -y pm-utils xscreensaver*
+RUN apt-get update && apt-get install -y vim less
+
+RUN echo 'source $STARTUPDIR/generate_container_user' >> $HOME/.bashrc
+
+RUN mkdir -p $STARTUPDIR
+COPY startup/ $STARTUPDIR
+
+### START CUSTOM STUFF ####
+
+ARG KASMVNC_PACKAGE_DIR
+COPY $KASMVNC_PACKAGE_DIR/kasmvncserver_*.deb /tmp
+RUN dpkg -i /tmp/*.deb; apt-get -yf install
+
+### END CUSTOM STUFF ###
+
+RUN chown -R 1000:0 $HOME
+USER 1000:ssl-cert
+WORKDIR $HOME
+
+ENTRYPOINT [ "/dockerstartup/vnc_startup.sh" ]
diff --git a/builder/dockerfile.kali_kali-rolling.build b/builder/dockerfile.kali_kali-rolling.build
new file mode 100644
index 0000000..6087895
--- /dev/null
+++ b/builder/dockerfile.kali_kali-rolling.build
@@ -0,0 +1,31 @@
+FROM kalilinux/kali-rolling:latest
+
+ENV KASMVNC_BUILD_OS kali
+ENV KASMVNC_BUILD_OS_CODENAME kali-rolling
+ENV XORG_VER 1.20.10
+ENV DEBIAN_FRONTEND noninteractive
+
+RUN grep '^deb'  /etc/apt/sources.list | sed 's#^deb#deb-src#' >> /etc/apt/sources.list
+
+RUN apt-get update && \
+      apt-get -y install sudo
+
+RUN DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends tzdata
+RUN apt-get update && apt-get -y build-dep xorg-server libxfont-dev
+RUN apt-get update && apt-get -y install cmake git libjpeg-dev libgnutls28-dev vim wget tightvncserver
+RUN apt-get update && apt-get -y install libjpeg-dev libpng-dev libtiff-dev libgif-dev libavcodec-dev libssl-dev
+
+# Additions for webp
+RUN cd /tmp && wget https://storage.googleapis.com/downloads.webmproject.org/releases/webp/libwebp-1.0.2.tar.gz
+RUN cd /tmp && tar -xzvf /tmp/libwebp-*
+RUN cd /tmp/libwebp-1.0.2 && \
+    ./configure --enable-static --disable-shared && \
+    make && make install
+
+RUN useradd -m docker && echo "docker:docker" | chpasswd && adduser docker sudo
+
+COPY . /src
+RUN chown -R docker:docker /src
+
+USER docker
+ENTRYPOINT ["/src/builder/build.sh"]
diff --git a/builder/dockerfile.kali_kali-rolling.deb.build b/builder/dockerfile.kali_kali-rolling.deb.build
new file mode 100644
index 0000000..8f0a2c5
--- /dev/null
+++ b/builder/dockerfile.kali_kali-rolling.deb.build
@@ -0,0 +1,12 @@
+FROM kalilinux/kali-rolling:latest
+
+ENV DEBIAN_FRONTEND noninteractive
+
+RUN apt-get update && \
+      apt-get -y install vim build-essential devscripts equivs
+
+# Install build-deps for the package.
+COPY ./debian/control /tmp
+RUN echo YYY | mk-build-deps --install --remove /tmp/control
+
+USER 1000
diff --git a/builder/dockerfile.ubuntu1804.deb.test b/builder/dockerfile.kali_kali-rolling.deb.test
similarity index 90%
rename from builder/dockerfile.ubuntu1804.deb.test
rename to builder/dockerfile.kali_kali-rolling.deb.test
index 4172490..9ee469c 100644
--- a/builder/dockerfile.ubuntu1804.deb.test
+++ b/builder/dockerfile.kali_kali-rolling.deb.test
@@ -1,4 +1,4 @@
-FROM ubuntu:18.04
+FROM kalilinux/kali-rolling:latest
 
 ENV DISPLAY=:1 \
     VNC_PORT=8443 \
@@ -40,13 +40,14 @@ COPY startup/ $STARTUPDIR
 
 ### START CUSTOM STUFF ####
 
-COPY build/*.deb /tmp
+ARG KASMVNC_PACKAGE_DIR
+COPY $KASMVNC_PACKAGE_DIR/kasmvncserver_*.deb /tmp
 RUN dpkg -i /tmp/*.deb; apt-get -yf install
 
 ### END CUSTOM STUFF ###
 
 RUN chown -R 1000:0 $HOME
-USER 1000:kasmvnc
+USER 1000:ssl-cert
 WORKDIR $HOME
 
 ENTRYPOINT [ "/dockerstartup/vnc_startup.sh" ]
diff --git a/builder/dockerfile.ubuntu1804.build b/builder/dockerfile.ubuntu_bionic.build
similarity index 97%
rename from builder/dockerfile.ubuntu1804.build
rename to builder/dockerfile.ubuntu_bionic.build
index 6c48eed..a21a716 100644
--- a/builder/dockerfile.ubuntu1804.build
+++ b/builder/dockerfile.ubuntu_bionic.build
@@ -1,7 +1,7 @@
 FROM ubuntu:18.04
 
 ENV KASMVNC_BUILD_OS ubuntu
-ENV KASMVNC_BUILD_OS_VER 18.04
+ENV KASMVNC_BUILD_OS_CODENAME bionic
 
 RUN sed -i 's$# deb-src$deb-src$' /etc/apt/sources.list
 
diff --git a/builder/dockerfile.ubuntu1804.deb.build b/builder/dockerfile.ubuntu_bionic.deb.build
similarity index 92%
rename from builder/dockerfile.ubuntu1804.deb.build
rename to builder/dockerfile.ubuntu_bionic.deb.build
index 3125fec..9063fd9 100644
--- a/builder/dockerfile.ubuntu1804.deb.build
+++ b/builder/dockerfile.ubuntu_bionic.deb.build
@@ -1,4 +1,4 @@
-FROM ubuntu:18.04
+FROM ubuntu:bionic
 
 RUN apt-get update && \
       apt-get -y install vim build-essential devscripts equivs
diff --git a/builder/dockerfile.ubuntu_bionic.deb.test b/builder/dockerfile.ubuntu_bionic.deb.test
new file mode 100644
index 0000000..9a0db27
--- /dev/null
+++ b/builder/dockerfile.ubuntu_bionic.deb.test
@@ -0,0 +1,53 @@
+FROM ubuntu:bionic
+
+ENV DISPLAY=:1 \
+    VNC_PORT=8443 \
+    VNC_RESOLUTION=1280x720 \
+    MAX_FRAME_RATE=24 \
+    VNCOPTIONS="-PreferBandwidth -DynamicQualityMin=4 -DynamicQualityMax=7" \
+    HOME=/home/user \
+    TERM=xterm \
+    STARTUPDIR=/dockerstartup \
+    INST_SCRIPTS=/dockerstartup/install \
+    KASM_RX_HOME=/dockerstartup/kasmrx \
+    DEBIAN_FRONTEND=noninteractive \
+    VNC_COL_DEPTH=24 \
+    VNC_RESOLUTION=1280x1024 \
+    VNC_PW=vncpassword \
+    VNC_USER=user \
+    VNC_VIEW_ONLY_PW=vncviewonlypassword \
+    LD_LIBRARY_PATH=/usr/local/lib/ \
+    OMP_WAIT_POLICY=PASSIVE \
+    SHELL=/bin/bash \
+    SINGLE_APPLICATION=0 \
+    KASMVNC_BUILD_OS=ubuntu \
+    KASMVNC_BUILD_OS_CODENAME=bionic
+
+EXPOSE $VNC_PORT
+
+WORKDIR $HOME
+
+### REQUIRED STUFF ###
+
+RUN apt-get update && apt-get install -y supervisor xfce4 xfce4-terminal xterm libnss-wrapper gettext wget
+RUN apt-get purge -y pm-utils xscreensaver*
+RUN apt-get update && apt-get install -y vim less
+
+RUN echo 'source $STARTUPDIR/generate_container_user' >> $HOME/.bashrc
+
+RUN mkdir -p $STARTUPDIR
+COPY startup/ $STARTUPDIR
+
+### START CUSTOM STUFF ####
+
+ARG KASMVNC_PACKAGE_DIR
+COPY $KASMVNC_PACKAGE_DIR/kasmvncserver_*.deb /tmp
+RUN dpkg -i /tmp/*.deb; apt-get -yf install
+
+### END CUSTOM STUFF ###
+
+RUN chown -R 1000:0 $HOME
+USER 1000:ssl-cert
+WORKDIR $HOME
+
+ENTRYPOINT [ "/dockerstartup/vnc_startup.sh" ]
diff --git a/builder/dockerfile.ubuntu1804.test b/builder/dockerfile.ubuntu_bionic.test
similarity index 89%
rename from builder/dockerfile.ubuntu1804.test
rename to builder/dockerfile.ubuntu_bionic.test
index a734c58..35470ff 100644
--- a/builder/dockerfile.ubuntu1804.test
+++ b/builder/dockerfile.ubuntu_bionic.test
@@ -21,7 +21,7 @@ ENV DISPLAY=:1 \
     SHELL=/bin/bash \
     SINGLE_APPLICATION=0 \
     KASMVNC_BUILD_OS=ubuntu \
-    KASMVNC_BUILD_OS_VER=18.04
+    KASMVNC_BUILD_OS_CODENAME=bionic
 
 EXPOSE $VNC_PORT
 
@@ -39,8 +39,8 @@ COPY startup/ $STARTUPDIR
 
 ### START CUSTOM STUFF ####
 
-COPY build/kasmvnc.${KASMVNC_BUILD_OS}_${KASMVNC_BUILD_OS_VER}.tar.gz /tmp/
-RUN tar -xzvf /tmp/kasmvnc.${KASMVNC_BUILD_OS}_${KASMVNC_BUILD_OS_VER}.tar.gz --strip 1 -C /
+COPY build/kasmvnc.${KASMVNC_BUILD_OS}_${KASMVNC_BUILD_OS_CODENAME}.tar.gz /tmp/
+RUN tar -xzvf /tmp/kasmvnc.${KASMVNC_BUILD_OS}_${KASMVNC_BUILD_OS_CODENAME}.tar.gz --strip 1 -C /
 
 ### END CUSTOM STUFF ###
 
diff --git a/builder/dockerfile.ubuntu2004.build b/builder/dockerfile.ubuntu_focal.build
similarity index 87%
rename from builder/dockerfile.ubuntu2004.build
rename to builder/dockerfile.ubuntu_focal.build
index 5540232..9c52a77 100644
--- a/builder/dockerfile.ubuntu2004.build
+++ b/builder/dockerfile.ubuntu_focal.build
@@ -1,7 +1,7 @@
-FROM ubuntu:20.04
+FROM ubuntu:focal
 
 ENV KASMVNC_BUILD_OS ubuntu
-ENV KASMVNC_BUILD_OS_VER 20.04
+ENV KASMVNC_BUILD_OS_CODENAME focal
 ENV XORG_VER 1.20.8
 ENV DEBIAN_FRONTEND noninteractive
 
@@ -10,7 +10,7 @@ RUN sed -i 's$# deb-src$deb-src$' /etc/apt/sources.list
 RUN apt-get update && \
       apt-get -y install sudo
 
-RUN DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends tzdata
+RUN apt-get update && apt-get install -y --no-install-recommends tzdata
 RUN apt-get update && apt-get -y build-dep xorg-server libxfont-dev
 RUN apt-get update && apt-get -y install cmake git libjpeg-dev libgnutls28-dev vim wget tightvncserver
 RUN apt-get update && apt-get -y install libjpeg-dev libpng-dev libtiff-dev libgif-dev libavcodec-dev libssl-dev
diff --git a/builder/dockerfile.ubuntu_focal.deb.build b/builder/dockerfile.ubuntu_focal.deb.build
new file mode 100644
index 0000000..703ce2b
--- /dev/null
+++ b/builder/dockerfile.ubuntu_focal.deb.build
@@ -0,0 +1,12 @@
+FROM ubuntu:focal
+
+ENV DEBIAN_FRONTEND noninteractive
+
+RUN apt-get update && \
+      apt-get -y install vim build-essential devscripts equivs
+
+# Install build-deps for the package.
+COPY ./debian/control /tmp
+RUN echo YYY | mk-build-deps --install --remove /tmp/control
+
+USER 1000
diff --git a/builder/dockerfile.ubuntu_focal.deb.test b/builder/dockerfile.ubuntu_focal.deb.test
new file mode 100644
index 0000000..4d1c50b
--- /dev/null
+++ b/builder/dockerfile.ubuntu_focal.deb.test
@@ -0,0 +1,53 @@
+FROM ubuntu:focal
+
+ENV DISPLAY=:1 \
+    VNC_PORT=8443 \
+    VNC_RESOLUTION=1280x720 \
+    MAX_FRAME_RATE=24 \
+    VNCOPTIONS="-PreferBandwidth -DynamicQualityMin=4 -DynamicQualityMax=7" \
+    HOME=/home/user \
+    TERM=xterm \
+    STARTUPDIR=/dockerstartup \
+    INST_SCRIPTS=/dockerstartup/install \
+    KASM_RX_HOME=/dockerstartup/kasmrx \
+    DEBIAN_FRONTEND=noninteractive \
+    VNC_COL_DEPTH=24 \
+    VNC_RESOLUTION=1280x1024 \
+    VNC_PW=vncpassword \
+    VNC_USER=user \
+    VNC_VIEW_ONLY_PW=vncviewonlypassword \
+    LD_LIBRARY_PATH=/usr/local/lib/ \
+    OMP_WAIT_POLICY=PASSIVE \
+    SHELL=/bin/bash \
+    SINGLE_APPLICATION=0 \
+    KASMVNC_BUILD_OS=ubuntu \
+    KASMVNC_BUILD_OS_CODENAME=bionic
+
+EXPOSE $VNC_PORT
+
+WORKDIR $HOME
+
+### REQUIRED STUFF ###
+
+RUN apt-get update && apt-get install -y supervisor xfce4 xfce4-terminal xterm libnss-wrapper gettext wget
+RUN apt-get purge -y pm-utils xscreensaver*
+RUN apt-get update && apt-get install -y vim less
+
+RUN echo 'source $STARTUPDIR/generate_container_user' >> $HOME/.bashrc
+
+RUN mkdir -p $STARTUPDIR
+COPY startup/ $STARTUPDIR
+
+### START CUSTOM STUFF ####
+
+ARG KASMVNC_PACKAGE_DIR
+COPY $KASMVNC_PACKAGE_DIR/kasmvncserver_*.deb /tmp
+RUN dpkg -i /tmp/*.deb; apt-get -yf install
+
+### END CUSTOM STUFF ###
+
+RUN chown -R 1000:0 $HOME
+USER 1000:ssl-cert
+WORKDIR $HOME
+
+ENTRYPOINT [ "/dockerstartup/vnc_startup.sh" ]
diff --git a/builder/dockerfile.ubuntu2004.test b/builder/dockerfile.ubuntu_focal.test
similarity index 87%
rename from builder/dockerfile.ubuntu2004.test
rename to builder/dockerfile.ubuntu_focal.test
index 37da8e8..18bf413 100644
--- a/builder/dockerfile.ubuntu2004.test
+++ b/builder/dockerfile.ubuntu_focal.test
@@ -1,4 +1,4 @@
-FROM ubuntu:20.04
+FROM ubuntu:focal
 
 ENV DISPLAY=:1 \
     VNC_PORT=8443 \
@@ -21,7 +21,7 @@ ENV DISPLAY=:1 \
     SHELL=/bin/bash \
     SINGLE_APPLICATION=0 \
     KASMVNC_BUILD_OS=ubuntu \
-    KASMVNC_BUILD_OS_VER=20.04
+    KASMVNC_BUILD_OS_CODENAME=focal
 
 EXPOSE $VNC_PORT
 
@@ -39,8 +39,8 @@ COPY startup/ $STARTUPDIR
 
 ### START CUSTOM STUFF ####
 
-COPY build/kasmvnc.${KASMVNC_BUILD_OS}_${KASMVNC_BUILD_OS_VER}.tar.gz /tmp/
-RUN tar -xzvf /tmp/kasmvnc.${KASMVNC_BUILD_OS}_${KASMVNC_BUILD_OS_VER}.tar.gz --strip 1 -C /
+COPY build/kasmvnc.${KASMVNC_BUILD_OS}_${KASMVNC_BUILD_OS_CODENAME}.tar.gz /tmp/
+RUN tar -xzvf /tmp/kasmvnc.${KASMVNC_BUILD_OS}_${KASMVNC_BUILD_OS_CODENAME}.tar.gz --strip 1 -C /
 
 ### END CUSTOM STUFF ###
 
diff --git a/builder/os_ver_cli.sh b/builder/os_ver_cli.sh
new file mode 100644
index 0000000..e1e230f
--- /dev/null
+++ b/builder/os_ver_cli.sh
@@ -0,0 +1,8 @@
+default_os=ubuntu
+default_os_codename=bionic
+
+os=${1:-$default_os}
+os_codename=${2:-$default_os_codename}
+os_image="$os:$os_codename"
+
+echo "Building for $os_image"
diff --git a/builder/startup/generate_container_user b/builder/startup/generate_container_user
index b259e7c..cbda373 100755
--- a/builder/startup/generate_container_user
+++ b/builder/startup/generate_container_user
@@ -1,3 +1,19 @@
+detect_libnss_wrapper() {
+  if $(which dpkg &>/dev/null); then
+    libnss_wrapper_file=$(dpkg -S libnss_wrapper.so | awk -F' ' '{ print $2 }')
+    return
+  fi
+
+  if [ -r /usr/lib/libnss_wrapper.so ]; then
+      libnss_wrapper_file=/usr/lib/libnss_wrapper.so
+  elif [ -r /usr/lib64/libnss_wrapper.so ]; then
+      libnss_wrapper_file=/usr/lib64/libnss_wrapper.so
+  else
+      echo "no libnss_wrapper.so installed!"
+      exit 1
+  fi
+}
+
 # Set current user in nss_wrapper
 USER_ID=$(id -u)
 GROUP_ID=$(id -g)
@@ -24,14 +40,7 @@ if [ x"$USER_ID" != x"0" ]; then
     export NSS_WRAPPER_PASSWD
     export NSS_WRAPPER_GROUP
 
-    if [ -r /usr/lib/libnss_wrapper.so ]; then
-        LD_PRELOAD=/usr/lib/libnss_wrapper.so
-    elif [ -r /usr/lib64/libnss_wrapper.so ]; then
-        LD_PRELOAD=/usr/lib64/libnss_wrapper.so
-    else
-        echo "no libnss_wrapper.so installed!"
-        exit 1
-    fi
-    echo "nss_wrapper location: $LD_PRELOAD"
-    export LD_PRELOAD
+    detect_libnss_wrapper
+    echo "nss_wrapper location: $libnss_wrapper_file"
+    export LD_PRELOAD="$libnss_wrapper_file"
 fi
diff --git a/builder/startup/vnc_startup.sh b/builder/startup/vnc_startup.sh
index 27e8f66..b2c3c59 100755
--- a/builder/startup/vnc_startup.sh
+++ b/builder/startup/vnc_startup.sh
@@ -21,16 +21,17 @@ detect_www_dir() {
 
 detect_cert_location() {
   local tarball_cert="$HOME/.vnc/self.pem"
-  local package_cert="/etc/kasmvnc/server.pem"
-  local use_cert=
-
-  if [[ -f "$package_cert" ]]; then
-    use_cert="$package_cert"
+  local deb_cert="/etc/ssl/certs/ssl-cert-snakeoil.pem"
+  local deb_key="/etc/ssl/private/ssl-cert-snakeoil.key"
+  local rpm_cert="/etc/pki/tls/private/kasmvnc.pem"
+
+  if [[ -f "$deb_cert" ]]; then
+    cert_option="-cert $deb_cert -key $deb_key"
+  elif [[ -f "$rpm_cert" ]]; then
+    cert_option="-cert $rpm_cert"
   else
-    use_cert="$tarball_cert"
+    cert_option="-cert $tarball_cert"
   fi
-
-  cert_option="-cert $use_cert"
 }
 
 ## resolve_vnc_connection
diff --git a/builder/test-deb b/builder/test-deb
index 231b9ee..dacd3d0 100755
--- a/builder/test-deb
+++ b/builder/test-deb
@@ -3,6 +3,10 @@
 set -e
 
 cd "$(dirname "$0")"
+. ./os_ver_cli.sh
 
-docker build -t kasmvnctester-deb:18.04 -f dockerfile.ubuntu1804.deb.test .
-#docker run -it -p 443:8443 --rm -e "VNC_USER=username" -e "VNC_PW=password123" kasmvnctester-deb:18.04
+docker build --build-arg KASMVNC_PACKAGE_DIR="build/${os_codename}" \
+  -t kasmvnctester_${os}:$os_codename \
+  -f dockerfile.${os}_${os_codename}.deb.test .
+echo docker run -it -p 443:8443 --rm -e "VNC_USER=foo" -e "VNC_PW=bar" \
+  kasmvnctester_${os}:$os_codename
diff --git a/builder/test-deb-barebones b/builder/test-deb-barebones
new file mode 100755
index 0000000..36010bb
--- /dev/null
+++ b/builder/test-deb-barebones
@@ -0,0 +1,14 @@
+#!/bin/bash
+
+set -e
+
+cd "$(dirname "$0")"
+os="debian"
+os_codename="buster"
+
+docker build --build-arg KASMVNC_PACKAGE_DIR="build/${os_codename}" \
+  -t kasmvnctester_barebones_${os}:$os_codename \
+  -f dockerfile.${os}_${os_codename}.barebones.deb.test .
+echo
+echo "You will be asked to set password. User name is docker."
+docker run -it -p 443:8443 --rm kasmvnctester_barebones_${os}:$os_codename
diff --git a/builder/test-rpm b/builder/test-rpm
new file mode 100755
index 0000000..b352962
--- /dev/null
+++ b/builder/test-rpm
@@ -0,0 +1,14 @@
+#!/bin/bash
+
+set -e
+
+cd "$(dirname "$0")"
+. ./os_ver_cli.sh
+
+echo kasmvnctester_${os}:$os_codename
+docker build --build-arg \
+  KASMVNC_PACKAGE_DIR="build/${os}_${os_codename}" \
+  -t kasmvnctester_${os}:$os_codename \
+  -f dockerfile.${os}_${os_codename}.rpm.test .
+echo docker run -it -p 443:8443 --rm -e "VNC_USER=foo" -e "VNC_PW=bar" \
+  kasmvnctester_${os}:$os_codename
diff --git a/builder/test-rpm-barebones b/builder/test-rpm-barebones
new file mode 100755
index 0000000..e8ba9cd
--- /dev/null
+++ b/builder/test-rpm-barebones
@@ -0,0 +1,13 @@
+#!/bin/bash
+
+set -e
+
+cd "$(dirname "$0")"
+os="centos"
+os_codename="core"
+
+docker build --build-arg KASMVNC_PACKAGE_DIR="build/${os}_${os_codename}" \
+  -t kasmvnctester_barebones_${os}:$os_codename \
+  -f dockerfile.${os}_${os_codename}.barebones.rpm.test .
+docker run -it -p 443:8443 --rm -e "VNC_USER=foo" -e "VNC_PW=bar" \
+  kasmvnctester_barebones_${os}:$os_codename
diff --git a/centos/kasmvncserver.spec b/centos/kasmvncserver.spec
new file mode 100644
index 0000000..c456a2b
--- /dev/null
+++ b/centos/kasmvncserver.spec
@@ -0,0 +1,81 @@
+Name:           kasmvncserver
+Version:        0.9.1~beta
+Release:        1%{?dist}
+Summary:        Lorem ipsum
+
+License: GPLv2+
+URL: https://github.com/kasmtech/KasmVNC
+
+BuildRequires: rsync
+Requires: xorg-x11-xauth, xorg-x11-xkb-utils, xkeyboard-config, xorg-x11-server-utils, openssl, perl
+Conflicts: tigervnc-server
+
+%description
+
+Lorem ipsum
+
+%prep
+
+%install
+rm -rf $RPM_BUILD_ROOT
+DESTDIR=$RPM_BUILD_ROOT make -f /src/debian/Makefile.to_fakebuild_tar_package install
+
+%files
+/usr/bin/*
+/usr/share/man/man1/*
+/usr/share/kasmvnc/www
+
+%license /usr/share/doc/kasmvncserver/LICENCE.TXT
+%doc /usr/share/doc/kasmvncserver/README.md
+
+%changelog
+* Fri Feb 12 2021 KasmTech <info@kasmweb.com> - 0.9.1~beta-1
+- Initial release of the rpm package.
+
+%post
+  bindir=/usr/bin
+  mandir=/usr/share/man
+  commands="kasmvncserver kasmvncpasswd kasmvncconfig Xkasmvnc"
+
+  for kasm_command in $commands; do
+    generic_command=`echo "$kasm_command" | sed -e 's/kasm//'`;
+    update-alternatives --install "$bindir/$generic_command" \
+      "$generic_command" "$bindir/$kasm_command" 90 \
+      --slave "$mandir/man1/$generic_command.1.gz" "$generic_command.1.gz" \
+        "$mandir/man1/$kasm_command.1.gz"
+  done
+
+  kasmvnc_group="kasmvnc"
+
+  create_kasmvnc_group() {
+    if ! getent group "$kasmvnc_group" >/dev/null; then
+	    groupadd --system "$kasmvnc_group"
+    fi
+  }
+
+  make_self_signed_certificate() {
+    local cert_file=/etc/pki/tls/private/kasmvnc.pem
+    [ -f "$cert_file" ] && return 0
+
+    openssl req -x509 -nodes -days 3650 -newkey rsa:2048 \
+      -keyout "$cert_file" \
+      -out "$cert_file" -subj \
+      "/C=US/ST=VA/L=None/O=None/OU=DoFu/CN=kasm/emailAddress=none@none.none"
+    chgrp "$kasmvnc_group" "$cert_file"
+    chmod 640 "$cert_file"
+  }
+
+  create_kasmvnc_group
+  make_self_signed_certificate
+
+%postun
+  bindir=/usr/bin
+  mandir=/usr/share/man
+  commands="kasmvncserver kasmvncpasswd kasmvncconfig Xkasmvnc"
+
+  for kasm_command in $commands; do
+    generic_command=`echo "$kasm_command" | sed -e 's/kasm//'`;
+    update-alternatives --remove "$generic_command" "$bindir/$kasm_command"
+  done
+
+  rm -f /etc/pki/tls/private/kasmvnc.pem
diff --git a/common/network/TcpSocket.cxx b/common/network/TcpSocket.cxx
index ab05eeb..de667d0 100644
--- a/common/network/TcpSocket.cxx
+++ b/common/network/TcpSocket.cxx
@@ -1,15 +1,15 @@
 /* Copyright (C) 2002-2005 RealVNC Ltd.  All Rights Reserved.
- * 
+ *
  * This is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation; either version 2 of the License, or
  * (at your option) any later version.
- * 
+ *
  * This software is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
- * 
+ *
  * You should have received a copy of the GNU General Public License
  * along with this software; if not, write to the Free Software
  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307,
@@ -38,6 +38,7 @@
 #include <sys/un.h>
 #include <stdlib.h>
 #include <unistd.h>
+#include <pthread.h>
 #include <wordexp.h>
 #include "websocket.h"
 
diff --git a/common/network/websocket.c b/common/network/websocket.c
index 3bc3b7f..6585402 100644
--- a/common/network/websocket.c
+++ b/common/network/websocket.c
@@ -160,12 +160,14 @@ ws_ctx_t *ws_socket_ssl(ws_ctx_t *ctx, int socket, char * certfile, char * keyfi
 
     }
 
-    ctx->ssl_ctx = SSL_CTX_new(TLSv1_server_method());
+    ctx->ssl_ctx = SSL_CTX_new(SSLv23_server_method());
     if (ctx->ssl_ctx == NULL) {
         ERR_print_errors_fp(stderr);
         fatal("Failed to configure SSL context");
     }
 
+    SSL_CTX_set_options(ctx->ssl_ctx, SSL_OP_NO_SSLv2 | SSL_OP_NO_SSLv3);
+
     if (SSL_CTX_use_PrivateKey_file(ctx->ssl_ctx, use_keyfile,
                                     SSL_FILETYPE_PEM) <= 0) {
         sprintf(msg, "Unable to load private key file %s\n", use_keyfile);
diff --git a/debian/Makefile.to_fakebuild_tar_package b/debian/Makefile.to_fakebuild_tar_package
index 966afcf..f6d3f7f 100644
--- a/debian/Makefile.to_fakebuild_tar_package
+++ b/debian/Makefile.to_fakebuild_tar_package
@@ -1,4 +1,11 @@
-TARBALL := builder/build/kasmvnc.ubuntu_18.04.tar.gz
+TARGET_OS := $(shell lsb_release -is | tr '[:upper:]' '[:lower:]')
+TARGET_OS_CODENAME := $(shell lsb_release -cs | tr '[:upper:]' '[:lower:]')
+ifeq ($(TARGET_OS), centos)
+	TARBALL_DIR := $$RPM_SOURCE_DIR
+else
+	TARBALL_DIR := builder/build
+endif
+TARBALL := $(TARBALL_DIR)/kasmvnc.$(TARGET_OS)_$(TARGET_OS_CODENAME).tar.gz
 TAR_DATA := $(shell mktemp -d)
 SRC := $(TAR_DATA)/usr/local
 SRC_BIN := $(SRC)/bin
@@ -15,8 +22,7 @@ install: unpack_tarball
 	cp $(SRC_BIN)/kasmvncpasswd $(DESTDIR)/usr/bin/
 	cp -r $(SRC)/share/doc/kasmvnc*/* $(DESTDIR)/usr/share/doc/kasmvncserver/
 	rsync -r --exclude '.git*' --exclude po2js --exclude xgettext-html \
-	  --exclude genkeysymdef.js --exclude use_require.js \
-	  --exclude .eslintrc \
+	  --exclude www/utils/ --exclude .eslintrc \
 	  $(SRC)/share/kasmvnc $(DESTDIR)/usr/share
 	cp $(SRC)/man/man1/Xvnc.1 $(DESTDIR)/usr/share/man/man1/Xkasmvnc.1
 	cp $(SRC)/share/man/man1/vncserver.1 $(DST_MAN)/kasmvncserver.1
diff --git a/debian/control b/debian/control
index 6f6f82a..979b52e 100644
--- a/debian/control
+++ b/debian/control
@@ -3,7 +3,7 @@ Section: x11
 Priority: optional
 Maintainer: Kasm Technologies LLC <info@kasmweb.com>
 Build-Depends: debhelper (>= 11), rsync, libjpeg-dev, libjpeg-dev, libpng-dev,
-  libtiff-dev, libgif-dev, libavcodec-dev, libssl-dev, libgl1, libxfont2
+  libtiff-dev, libgif-dev, libavcodec-dev, libssl-dev, libgl1, libxfont2, libsm6
 Standards-Version: 4.1.3
 Homepage: https://github.com/kasmtech/KasmVNC
 #Vcs-Browser: https://salsa.debian.org/debian/kasmvnc
@@ -11,7 +11,8 @@ Homepage: https://github.com/kasmtech/KasmVNC
 
 Package: kasmvncserver
 Architecture: amd64
-Depends: ${shlibs:Depends}, ${misc:Depends}, ${perl:Depends}, ssl-cert, python, xauth
+Depends: ${shlibs:Depends}, ${misc:Depends}, ${perl:Depends}, ssl-cert, xauth,
+  x11-xkb-utils, xkb-data, procps
 Provides: vnc-server
 Description: virtual network computing server with web interface
  Lorem ipsum
diff --git a/debian/dirs b/debian/dirs
deleted file mode 100644
index ae5bbdc..0000000
--- a/debian/dirs
+++ /dev/null
@@ -1 +0,0 @@
-etc/kasmvnc
diff --git a/debian/patches/fix-kasmvncserver-perl-hashbang.patch b/debian/patches/fix-kasmvncserver-perl-hashbang.patch
new file mode 100644
index 0000000..4fa9c69
--- /dev/null
+++ b/debian/patches/fix-kasmvncserver-perl-hashbang.patch
@@ -0,0 +1,10 @@
+Description: Lintian complains about #!/usr/bin/env perl.
+Author: Dmitry Maksyoma <ledestin@gmail.com>
+--- a/unix/vncserver
++++ b/unix/vncserver
+@@ -1,4 +1,4 @@
+-#!/usr/bin/env perl
++#!/usr/bin/perl
+ #
+ #  Copyright (C) 2009-2010 D. R. Commander.  All Rights Reserved.
+ #  Copyright (C) 2005-2006 Sun Microsystems, Inc.  All Rights Reserved.
diff --git a/debian/patches/series b/debian/patches/series
new file mode 100644
index 0000000..7312ab9
--- /dev/null
+++ b/debian/patches/series
@@ -0,0 +1 @@
+fix-kasmvncserver-perl-hashbang.patch
diff --git a/debian/postinst b/debian/postinst
index c92f80a..8a1f407 100644
--- a/debian/postinst
+++ b/debian/postinst
@@ -17,27 +17,6 @@ set -e
 # for details, see https://www.debian.org/doc/debian-policy/ or
 # the debian-policy package
 
-kasmvnc_group="kasmvnc"
-
-create_kasmvnc_group() {
-  if ! getent group "$kasmvnc_group" >/dev/null; then
-          addgroup --quiet --system "$kasmvnc_group"
-  fi
-}
-
-make_self_signed_certificate() {
-  local cert_file=/etc/kasmvnc/server.pem
-  [ -f "$cert_file" ] && return 0
-
-  openssl req -x509 -nodes -days 3650 -newkey rsa:2048 -keyout "$cert_file" \
-  -out "$cert_file" -subj \
-  "/C=US/ST=VA/L=None/O=None/OU=DoFu/CN=kasm/emailAddress=none@none.none"
-  chgrp "$kasmvnc_group" "$cert_file"
-  chmod g+r "$cert_file"
-}
-
-create_kasmvnc_group
-
 case "$1" in
     configure)
       bindir=/usr/bin
@@ -51,8 +30,6 @@ case "$1" in
           --slave "$mandir/man1/$generic_command.1.gz" "$generic_command.1.gz" \
             "$mandir/man1/$kasm_command.1.gz"
       done
-
-      make_self_signed_certificate
     ;;
 
     abort-upgrade|abort-remove|abort-deconfigure)
diff --git a/debian/postrm b/debian/postrm.ex
similarity index 95%
rename from debian/postrm
rename to debian/postrm.ex
index 2d34fa5..9f9ec2c 100644
--- a/debian/postrm
+++ b/debian/postrm.ex
@@ -20,9 +20,6 @@ set -e
 
 
 case "$1" in
-    purge)
-      rm -r /etc/kasmvnc
-    ;;
     purge|remove|upgrade|failed-upgrade|abort-install|abort-upgrade|disappear)
     ;;
 
diff --git a/unix/vncserver b/unix/vncserver
index c19fd3e..04c758e 100644
--- a/unix/vncserver
+++ b/unix/vncserver
@@ -16,10 +16,9 @@
 #  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 #  GNU General Public License for more details.
 #
-#  You should have received a copy of the GNU General Public License
-#  along with this software; if not, write to the Free Software
-#  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307,
-#  USA.
+#  You should have received a copy of the GNU General Public License along
+#  with this program; if not, write to the Free Software Foundation, Inc.,
+#  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 #
 
 #