1. TwinCAT 3 PLC Lib: Tc2_DataExchange
2. Global constants
3. Library version

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:

Global_Version

VAR_GLOBAL CONSTANT
    stLibVersion_Tc2_DataExchange : ST_LibVersion;
END_VAR

stLibVersion_Tc2_DataExchange: Version information of Tc2_DataExchange (type: ST_LibVersion)

To check whether the version you have is the version you need, use the function F_CmpLibVersion (defined in the Tc2_System library).

All other options for comparing library versions, which you may know from TwinCAT 2, are outdated!