diff --git a/.github/actions/pre-build/action.yml b/.github/actions/pre-build/action.yml
index 1de052d3..b4b51b6f 100644
--- a/.github/actions/pre-build/action.yml
+++ b/.github/actions/pre-build/action.yml
@@ -13,10 +13,17 @@ runs:
           echo "FAIRROOTPATH=${CVMDIR}/${{ matrix.os }}/fairroot/cpp20/v18.8.2_${{ matrix.fsv }}" >> $GITHUB_ENV
           echo "${SIMPATH}/bin" >> $GITHUB_PATH
         else
-          export SIMPATH=${CVMDIR}/${{ matrix.os }}/fairsoft/${{ matrix.fsv }}
-          echo "SIMPATH=${SIMPATH}" >> $GITHUB_ENV
-          echo "FAIRROOTPATH=${CVMDIR}/${{ matrix.os }}/fairroot/v18.8.2_${{ matrix.fsv }}" >> $GITHUB_ENV
-          echo "${SIMPATH}/bin" >> $GITHUB_PATH
+          if [ "${{ matrix.os }}" == "debian13" ]; then
+            export SIMPATH=${CVMDIR}/debian13/fairsoft/cpp17/jan24p6
+            echo "SIMPATH=${SIMPATH}" >> $GITHUB_ENV
+            echo "FAIRROOTPATH=${CVMDIR}/debian13/fairroot/cpp17/v18.8.2_jan24p6" >> $GITHUB_ENV
+            echo "${SIMPATH}/bin" >> $GITHUB_PATH         
+          else
+            export SIMPATH=${CVMDIR}/${{ matrix.os }}/fairsoft/${{ matrix.fsv }}
+            echo "SIMPATH=${SIMPATH}" >> $GITHUB_ENV
+            echo "FAIRROOTPATH=${CVMDIR}/${{ matrix.os }}/fairroot/v18.8.2_${{ matrix.fsv }}" >> $GITHUB_ENV
+            echo "${SIMPATH}/bin" >> $GITHUB_PATH
+          fi
         fi
         # variables for ccache
         echo "CCACHE_BASEDIR=${GITHUB_WORKSPACE}" >> $GITHUB_ENV
diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 8b245fcc..a73ddff1 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -53,7 +53,7 @@ jobs:
         # Here are the groups of repositories that need to be downloaded inside
         # r3broot. Each group is used by only one job.
         repos: [ sofia ]
-        os: [ debian11, debian12 ]
+        os: [ debian11, debian12 , debian13]
         fsv: [ jan24p5 ]
         cpp: [ 17 ]
         include:
@@ -74,7 +74,7 @@ jobs:
         # testing. Github hosted runners can have at most 4 cores. The number
         # of the cores can be increased with a larger runner, thus increasing
         # the speed of the run.
-        NUM_THREADS: 10
+        NUM_THREADS: 4
       # Options for the Docker container to be run with cvmfs.
       options: --user root --privileged  --ulimit nofile=10000:10000 --cap-add SYS_ADMIN --device /dev/fuse
 
diff --git a/README.md b/README.md
index 43b20136..cfae2f16 100755
--- a/README.md
+++ b/README.md
@@ -332,9 +332,9 @@ The following systems are tested regularly.
 | Almalinux   | x86\_64  | 9.3            | GCC 11.4.1    | 3.27.9 / 4.0.3  | C++17 / C++20   |
 | Almalinux   | x86\_64  | 9.4            | GCC 14.2.0    | 3.30.6          | C++17           |
 | RHEL        | x86\_64  | 9.6            | GCC 14.2.0    | 3.30.6          | C++17           |
-| Debian      | x86\_64  | 10             | GCC 8.3.0     | 3.27.4 / 4.0.3  | C++17           |
 | Debian      | x86\_64  | 11             | GCC 10.2.1    | 3.27.4 / 3.30.0 | C++17           |
 | Debian      | x86\_64  | 12             | GCC 12.2.0    | 3.27.4 / 3.30.0 | C++17 / C++20   |
+| Debian      | x86\_64  | 13             | GCC 14.2.0    | 3.31.6 / 4.0.3  | C++17           |
 | Ubuntu      | x86\_64  | 24.04          | GCC 13.3.0    | 3.28.3 / 4.0.3  | C++17 / C++20   |
 | Ubuntu      | x86\_64  | 25.04          | GCC 14.2.0    | 3.31.6 / 4.0.3  | C++17           |