Pin to xpress 9.5.0

.github/workflows/test_branches.yml

@@ -282,7 +282,7 @@ jobs:
                 || echo "WARNING: CPLEX Community Edition is not available"
             python -m pip install --cache-dir cache/pip gurobipy \
                 || echo "WARNING: Gurobi is not available"
-            python -m pip install --cache-dir cache/pip xpress \
+            python -m pip install --cache-dir cache/pip xpress==9.5.0 \
                 || echo "WARNING: Xpress Community Edition is not available"
             python -m pip install --cache-dir cache/pip maingopy \
                 || echo "WARNING: MAiNGO is not available"
@@ -367,7 +367,7 @@ jobs:
         if test -z "${{matrix.slim}}"; then
             PYVER=$(echo "py${{matrix.python}}" | sed 's/\.//g')
             echo "Installing for $PYVER"
-            for PKG in 'cplex>=12.10' docplex gurobi xpress cyipopt pymumps scip; do
+            for PKG in 'cplex>=12.10' docplex gurobi 'xpress=9.5.0' cyipopt pymumps scip; do
                 echo ""
                 echo "*** Install $PKG ***"
                 # conda can literally take an hour to determine that a