Library version
All libraries have a certain version. The version is indicated in the PLC library repository, for example. A global constant contains the information about the library version:
VAR_GLOBAL CONSTANT
stLibVersion_Tc3_IPCDiag : ST_LibVersion;
END_VAR
In order to check whether you are using the library version that you need, the function F_CmpLibVersion (defined in Tc2_System library) is available to you.