For anyone looking for a solution to a similar problem: * You should install a newer version of CodeSys (e.g. 3.5 SP19) * Open newer version of CodeSys * Import the project * Click File > Save Project as * Select the appropriate file type according to the target CodeSys version - in case of CodeSys 3.5 SP11 select Library files (CODESYS V3.5 SP11) (*.library) * Click Save Now you will be able to open the .library with the target CodeSys version.
For anyone looking for a solution to a similar problem: * You should install a newer version of CodeSys (e.g. 3.5 SP19) * Open newer version of CodeSys * Import the project * Click File > Save Project as * Select the appropriate file type according to the target CodeSys version - in case of CodeSys 3.5 SP19 select Library files (CODESYS V3.5 SP11) (*.library) * Click Save Now you will be able to open the .library with the target CodeSys version.