diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 50c8649b..d5bfa842 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -4,9 +4,10 @@ before_script:
 - apt-get update
 - apt-get install -y ca-certificates && apt-get clean
 - apt-get install -y pip && apt-get clean
-- apt-get install -y python3-sphinx && apt-get clean
+  # following ones get updated, so they are not installed from Debian package repo: python3-sphinx python3-pybtex-docutils
+  #- apt-get install -y python3-sphinx && apt-get clean
 - apt-get install -y jupyter-notebook && apt-get clean
-- apt-get install -y python3-anyio python3-greenlet python3-click python3-jupyter-server python3-sqlalchemy python3-latexcodec python3-nbclient python3-nest-asyncio python3-pybtex python3-pybtex-docutils python3-smmap python3-soupsieve python3-toml && apt-get clean && rm -r /var/lib/apt /usr/share/doc /usr/share/man
+- apt-get install -y python3-anyio python3-greenlet python3-click python3-jupyter-server python3-sqlalchemy python3-latexcodec python3-nbclient python3-nest-asyncio python3-pybtex python3-smmap python3-soupsieve python3-toml && apt-get clean && rm -r /var/lib/apt /usr/share/doc /usr/share/man
 - pip install jupyter-book && rm -r /root/.cache/pip
 
 pages:
diff --git a/Dockerfile b/Dockerfile
index a66d7a3d..64bbfd1b 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,7 +1,8 @@
 FROM debian:latest
 
 RUN apt-get update
-RUN apt-get install -y pip python3-sphinx jupyter-notebook python3-anyio python3-greenlet python3-click python3-jupyter-server python3-sqlalchemy python3-latexcodec python3-nbclient python3-nest-asyncio python3-pybtex python3-pybtex-docutils python3-smmap python3-soupsieve python3-toml && apt-get clean && rm -r /var/lib/apt /usr/share/doc /usr/share/man
+# following ones get updated, so they are not installed from Debian package repo: python3-sphinx python3-pybtex-docutils
+RUN apt-get install -y pip jupyter-notebook python3-anyio python3-greenlet python3-click python3-jupyter-server python3-sqlalchemy python3-latexcodec python3-nbclient python3-nest-asyncio python3-smmap python3-soupsieve python3-toml python3-pybtex && apt-get clean && rm -r /var/lib/apt /usr/share/doc /usr/share/man
 RUN pip install jupyter-book && rm -r /root/.cache/pip
 
 RUN mkdir -p /root/documentation