diff --git a/Documentation/ProjectFile/prj/processes/process/secondary_variables/secondary_variable/a_type.md b/Documentation/ProjectFile/prj/processes/process/secondary_variables/secondary_variable/a_type.md
index c0c5e84d40a20c6c15913b7d6dab02b67ab46575..ca579c8f6b380247394fe2a6aad52093cf31b069 100644
--- a/Documentation/ProjectFile/prj/processes/process/secondary_variables/secondary_variable/a_type.md
+++ b/Documentation/ProjectFile/prj/processes/process/secondary_variables/secondary_variable/a_type.md
@@ -1,6 +1 @@
-The type of the secondary variable.
-
-Can be <tt>static</tt> for secondary variables that don't need any further
-information from the project file in order to be computed;
-or <tt>dynamic</tt> if the functions providing some of the input data for
-computing the secondary variable are set up at runtime.
+Deprecated. This attribute is no longer used.
diff --git a/ProcessLib/Output/CreateSecondaryVariables.cpp b/ProcessLib/Output/CreateSecondaryVariables.cpp
index 8071e936d4bde9a8f6644dc3b325762d6472b46e..d42b78733aea7dc2cad2a4548dd5d0b3d280b6e2 100644
--- a/ProcessLib/Output/CreateSecondaryVariables.cpp
+++ b/ProcessLib/Output/CreateSecondaryVariables.cpp
@@ -37,7 +37,13 @@ void createSecondaryVariables(
     {
         auto const type =
             //! \ogs_file_attr{prj__processes__process__secondary_variables__secondary_variable__type}
-            sec_var_config.getConfigAttribute<std::string>("type");
+            sec_var_config.getConfigAttributeOptional<std::string>("type");
+        if (type)
+        {
+            WARN(
+                "Secondary variable type specification is deprecated and is "
+                "ignored. All secondary variable types are 'static'.");
+        }
 
         auto const internal_name =
             //! \ogs_file_attr{prj__processes__process__secondary_variables__secondary_variable__internal_name}