diff --git a/.github/workflows/stable-build.yml b/.github/workflows/stable-build.yml
index 0b6918e..26eff41 100644
--- a/.github/workflows/stable-build.yml
+++ b/.github/workflows/stable-build.yml
@@ -63,7 +63,7 @@ jobs:
     name: "Release image: DocumentServer${{ matrix.edition }}-nonExample"
     runs-on: ubuntu-latest
     needs: [build]
-    if: always()
+    if: ${{ false }}
     strategy:
       fail-fast: false
       matrix:
@@ -92,3 +92,39 @@ jobs:
           export TAG=${{ github.event.inputs.tag }}
           docker buildx bake -f docker-bake.hcl ${{ matrix.images }} --push
         shell: bash
+
+  build-ucs-ubuntu20:
+    name: "Release image: DocumentServer${{ matrix.edition }}-ucs"
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        edition: ["", "-ee"]
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v3
+
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v2
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v2
+
+      - name: Login to Docker Hub
+        uses: docker/login-action@v2
+        with:
+          username: ${{ secrets.DOCKER_HUB_USERNAME }}
+          password: ${{ secrets.DOCKER_HUB_ACCESS_TOKEN }}
+
+      - name: build UCS
+        run: |
+           set -eux
+           export PRODUCT_EDITION=${{ matrix.edition }}
+           export PACKAGE_BASEURL=${{ secrets.REPO_BASEURL_OLD }}/testing/ubuntu
+           export DOCKERFILE=Dockerfile
+           export BASE_IMAGE=ubuntu:20.04
+           export PG_VERSION=12
+           export TAG=${{ github.event.inputs.tag }}
+           export PACKAGE_VERSION=$( echo ${TAG} |  sed -E 's/(.*)\./\1-/')
+           docker buildx bake -f docker-bake.hcl documentserver-ucs --push
+        shell: bash
diff --git a/Dockerfile b/Dockerfile
index 8470c59..4e6ae96 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,7 +1,11 @@
-FROM ubuntu:22.04 as documentserver
+ARG BASE_IMAGE=ubuntu:22.04
+
+FROM ${BASE_IMAGE} as documentserver
 LABEL maintainer Ascensio System SIA <support@onlyoffice.com>
 
-ENV LANG=en_US.UTF-8 LANGUAGE=en_US:en LC_ALL=en_US.UTF-8 DEBIAN_FRONTEND=noninteractive PG_VERSION=14
+ARG PG_VERSION=14
+
+ENV LANG=en_US.UTF-8 LANGUAGE=en_US:en LC_ALL=en_US.UTF-8 DEBIAN_FRONTEND=noninteractive PG_VERSION=${PG_VERSION}
 
 ARG ONLYOFFICE_VALUE=onlyoffice
 
@@ -13,6 +17,7 @@ RUN echo "#!/bin/sh\nexit 0" > /usr/sbin/policy-rc.d && \
     chmod 644 /etc/apt/trusted.gpg.d/onlyoffice.gpg && \
     locale-gen en_US.UTF-8 && \
     echo ttf-mscorefonts-installer msttcorefonts/accepted-mscorefonts-eula select true | debconf-set-selections && \
+    wget -O - https://packagecloud.io/install/repositories/rabbitmq/rabbitmq-server/script.deb.sh | bash && \
     apt-get -yq install \
         adduser \
         apt-utils \
@@ -41,7 +46,7 @@ RUN echo "#!/bin/sh\nexit 0" > /usr/sbin/policy-rc.d && \
         postgresql \
         postgresql-client \
         pwgen \
-        rabbitmq-server \
+        rabbitmq-server=3.10* \
         redis-server \
         software-properties-common \
         sudo \
diff --git a/README.md b/README.md
index 5020dfd..4c384e3 100644
--- a/README.md
+++ b/README.md
@@ -25,6 +25,8 @@ Starting from version 6.0, Document Server is distributed as ONLYOFFICE Docs. It
 
 ONLYOFFICE Docs can be used as a part of ONLYOFFICE Workspace or with third-party sync&share solutions (e.g. Nextcloud, ownCloud, Seafile) to enable collaborative editing within their interface.
 
+***Important*** Please update `docker-enginge` to latest version (`20.10.21` as of writing this doc) before using it. We use `ubuntu:22.04` as base image and it older versions of docker have compatibility problems with it
+
 ## Functionality ##
 * ONLYOFFICE Document Editor
 * ONLYOFFICE Spreadsheet Editor
diff --git a/docker-bake.hcl b/docker-bake.hcl
index 0e25c8b..28396a6 100644
--- a/docker-bake.hcl
+++ b/docker-bake.hcl
@@ -50,6 +50,18 @@ variable "BUILD_CHANNEL" {
     default = ""
 }
 
+### ↓ Variables for UCS build ↓
+
+variable "BASE_IMAGE" {
+    default     = ""
+}
+
+variable "PG_VERSION" {
+    default     = ""
+}
+
+### ↑ Variables for UCS build ↑
+
 target "documentserver" {
     target = "documentserver"
     dockerfile = "${DOCKERFILE}"
@@ -85,6 +97,24 @@ target "documentserver-stable" {
     }
 }
 
+target "documentserver-ucs" {
+    target = "documentserver"
+    dockerfile = "${DOCKERFILE}"
+    tags = [
+           "docker.io/${COMPANY_NAME}/${PRODUCT_NAME}${PRODUCT_EDITION}-ucs:${TAG}"
+           ]
+    platforms = ["linux/amd64", "linux/arm64"]
+    args = {
+        "PRODUCT_EDITION": "${PRODUCT_EDITION}"
+        "PRODUCT_NAME": "${PRODUCT_NAME}"
+        "COMPANY_NAME": "${COMPANY_NAME}"
+        "PACKAGE_VERSION": "${PACKAGE_VERSION}"
+        "PACKAGE_BASEURL": "${PACKAGE_BASEURL}"
+        "BASE_IMAGE": "${BASE_IMAGE}"
+        "PG_VERSION": "${PG_VERSION}"
+    }
+}
+
 target "documentserver-nonexample" {
     target = "documentserver-nonexample"
     dockerfile = "production.dockerfile"
diff --git a/run-document-server.sh b/run-document-server.sh
index 482be89..91a96b5 100755
--- a/run-document-server.sh
+++ b/run-document-server.sh
@@ -73,7 +73,8 @@ NGINX_ONLYOFFICE_EXAMPLE_CONF="${NGINX_ONLYOFFICE_EXAMPLE_PATH}/includes/ds-exam
 
 NGINX_CONFIG_PATH="/etc/nginx/nginx.conf"
 NGINX_WORKER_PROCESSES=${NGINX_WORKER_PROCESSES:-1}
-NGINX_WORKER_CONNECTIONS=${NGINX_WORKER_CONNECTIONS:-$(ulimit -n)}
+# Limiting the maximum number of simultaneous connections due to possible memory shortage
+[ $(ulimit -n) -gt 1048576 ] && NGINX_WORKER_CONNECTIONS=${NGINX_WORKER_CONNECTIONS:-1048576} || NGINX_WORKER_CONNECTIONS=${NGINX_WORKER_CONNECTIONS:-$(ulimit -n)}
 
 JWT_ENABLED=${JWT_ENABLED:-true}
 
@@ -199,7 +200,7 @@ parse_rabbitmq_url(){
   # extract the host
   local hostport="$(echo ${url/$userpass@/} | cut -d/ -f1)"
   # by request - try to extract the port
-  local port="$(echo $hostport | sed -e 's,^.*:,:,g' -e 's,.*:\([0-9]*\).*,\1,g' -e 's,[^0-9],,g')"
+  local port="$(echo $hostport | grep : | sed -r 's_^.*:+|/.*$__g')"
 
   local host
   if [ -n "$port" ]; then