diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 65471b5a2c3af3940a77083f66fec40973ec205b..b9e6fb2424e92827f0beeeb26f658f6ec43c3b47 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -94,9 +94,6 @@ run_unit_tests_py311:
   extends: .run_unit_tests_pyXX
   image: python:3.11-bullseye
   script:
-    # Debian Bullseye ships with libboost-python linked to Python 3.9. Use the one from Debian Sid instead.
-    - echo 'deb http://deb.debian.org/debian sid main' >> /etc/apt/sources.list
-    - apt-get update -y && DEBIAN_FRONTEND=noninteractive apt-get install -y libboost-python1.74-dev
     - echo "run python3.11 unit tests /w coverage"
     - tox -e py311
 
@@ -104,9 +101,6 @@ run_unit_tests_py312:
   extends: .run_unit_tests_pyXX
   image: python:3.12-bullseye
   script:
-    # Debian Bullseye ships with libboost-python linked to Python 3.9. Use the one from Debian Sid instead.
-    - echo 'deb http://deb.debian.org/debian sid main' >> /etc/apt/sources.list
-    - apt-get update -y && DEBIAN_FRONTEND=noninteractive apt-get install -y libboost-python1.74-dev
     - echo "run python3.12 unit tests /w coverage"
     - tox -e py312