diff --git a/Applications/ApplicationsLib/ProjectData.cpp b/Applications/ApplicationsLib/ProjectData.cpp
index 7528926f0e8b2f19ada58eef18ca33059d1ec978..86266fbd74a128a99306e59f2156ba5a6ca90462 100644
--- a/Applications/ApplicationsLib/ProjectData.cpp
+++ b/Applications/ApplicationsLib/ProjectData.cpp
@@ -731,6 +731,9 @@ void ProjectData::parseProcesses(
 #ifdef OGS_BUILD_PROCESS_STOKESFLOW
             if (type == "StokesFlow")
         {
+            WARN(
+                "The StokesFlow process is deprecated and will be removed in "
+                "OGS-6.5.5.");
             switch (_mesh_vec[0]->getDimension())
             {
                 case 2:
@@ -752,6 +755,9 @@ void ProjectData::parseProcesses(
 #ifdef OGS_BUILD_PROCESS_TES
             if (type == "TES")
         {
+            WARN(
+                "The TES process is deprecated and will be removed in "
+                "OGS-6.5.5.");
             process = ProcessLib::TES::createTESProcess(
                 name, *_mesh_vec[0], std::move(jacobian_assembler),
                 _process_variables, _parameters, integration_order,
@@ -1033,6 +1039,9 @@ void ProjectData::parseProcesses(
 #ifdef OGS_BUILD_PROCESS_SMALLDEFORMATIONNONLOCAL
             if (type == "SMALL_DEFORMATION_NONLOCAL")
         {
+            WARN(
+                "The SMALL_DEFORMATION_NONLOCAL process is deprecated and will "
+                "be removed in OGS-6.5.5.");
             switch (_mesh_vec[0]->getDimension())
             {
                 case 2:
@@ -1145,6 +1154,9 @@ void ProjectData::parseProcesses(
 #ifdef OGS_BUILD_PROCESS_THERMOMECHANICALPHASEFIELD
             if (type == "THERMO_MECHANICAL_PHASE_FIELD")
         {
+            WARN(
+                "The THERMO_MECHANICAL_PHASE_FIELD process is deprecated and "
+                "will be removed in OGS-6.5.5.");
             switch (_mesh_vec[0]->getDimension())
             {
                 case 2:
@@ -1290,6 +1302,9 @@ void ProjectData::parseProcesses(
 #ifdef OGS_BUILD_PROCESS_TWOPHASEFLOWWITHPRHO
             if (type == "TWOPHASE_FLOW_PRHO")
         {
+            WARN(
+                "The TWOPHASE_FLOW_PRHO process is deprecated and will be "
+                "removed in OGS-6.5.5.");
             process = ProcessLib::TwoPhaseFlowWithPrho::
                 createTwoPhaseFlowWithPrhoProcess(
                     name, *_mesh_vec[0], std::move(jacobian_assembler),
diff --git a/scripts/ci/extends/template-build-linux.yml b/scripts/ci/extends/template-build-linux.yml
index 18e30d74afa3c03c5274f27efea0c5bcd814d586..4f833282e5fe11ccd4df6570bfdbe220e1816f34 100644
--- a/scripts/ci/extends/template-build-linux.yml
+++ b/scripts/ci/extends/template-build-linux.yml
@@ -13,7 +13,7 @@
     - if [[ "$OSTYPE" == "darwin"* ]] ; then readlink_cmd=greadlink; else readlink_cmd=readlink; fi
     - ln -s `$readlink_cmd -f $build_dir_full` build/${CMAKE_PRESET}-${CI_JOB_NAME_SLUG}-${CI_JOB_ID}
     - ([[ $BUILD_CTEST_LARGE_ON_MASTER && "${CI_COMMIT_BRANCH}" == "master" ]]) && export BUILD_CTEST_LARGE=true
-    - cmake --preset=$CMAKE_PRESET --log-level=VERBOSE -Wno-dev $CMAKE_ARGS
+    - cmake --preset=$CMAKE_PRESET --log-level=VERBOSE -Wno-dev $CMAKE_ARGS -DOGS_BUILD_DEPRECATED_PROCESSES=ON
     # Activate .venv via .envrc
     - test -f $build_dir_full/.venv/bin/activate && source $build_dir_full/.envrc
     - |
diff --git a/scripts/ci/extends/template-build-win.yml b/scripts/ci/extends/template-build-win.yml
index 467f8170773abad094dc1a125536e611ede18d89..e549e1cfb9ea0b1e7652c79142c86ec8e98dcdd9 100644
--- a/scripts/ci/extends/template-build-win.yml
+++ b/scripts/ci/extends/template-build-win.yml
@@ -15,7 +15,7 @@
     - mkdir build # We are inside the OGS source directory, now. This "build" dir will be, too.
     # Create symlink https://stackoverflow.com/a/34905638/80480
     - cmd /c mklink /D $artifacts_dir $env:CI_PROJECT_DIR\$build_directory_full
-    - $cmake_cmd = "cmake --preset=$env:CMAKE_PRESET --log-level=VERBOSE -Wno-dev $env:CMAKE_ARGS"
+    - $cmake_cmd = "cmake --preset=$env:CMAKE_PRESET --log-level=VERBOSE -Wno-dev $env:CMAKE_ARGS -DOGS_BUILD_DEPRECATED_PROCESSES=ON"
     - $cmake_cmd
     - Invoke-Expression $cmake_cmd
     # Activate .venv
diff --git a/scripts/cmake/ProcessesSetup.cmake b/scripts/cmake/ProcessesSetup.cmake
index 8ef8517ea8d6e6b52b8c5d1ac168c481753cde9c..9acebf1b6f362fb26ff9cce7ac561de97e77984b 100644
--- a/scripts/cmake/ProcessesSetup.cmake
+++ b/scripts/cmake/ProcessesSetup.cmake
@@ -2,7 +2,6 @@
 # processes to be build.
 set(_processes_list
     ComponentTransport
-    StokesFlow
     HT
     HeatConduction
     HeatTransportBHE
@@ -14,19 +13,25 @@ set(_processes_list
     RichardsFlow
     RichardsMechanics
     SmallDeformation
-    SmallDeformationNonlocal
     SteadyStateDiffusion
-    TES
     TH2M
     ThermalTwoPhaseFlowWithPP
     ThermoHydroMechanics
-    ThermoMechanicalPhaseField
     ThermoMechanics
     ThermoRichardsFlow
     TwoPhaseFlowWithPP
-    TwoPhaseFlowWithPrho
     WellboreSimulator
 )
+option(OGS_BUILD_DEPRECATED_PROCESSES "Build deprecated processes" OFF)
+if(OGS_BUILD_DEPRECATED_PROCESSES)
+    set(_deprecated_processes TwoPhaseFlowWithPrho SmallDeformationNonlocal
+        TES ThermoMechanicalPhaseField StokesFlow)
+    list(APPEND _processes_list ${_deprecated_processes})
+    foreach(process ${_deprecated_processes})
+        message(WARNING "${process} is deprecated and will be removed in OGS-6.5.5.")
+    endforeach()
+endif()
+
 if(OGS_USE_MFRONT)
     set(_processes_list ${_processes_list} LargeDeformation)
 endif()