Hi Ben,
If the project is already well along, and using windows and doors from the 11 library, then you may be best off just leaving those parts, and only using the new library for newly inserted elements. Each situation is somewhat unique.
As Tran said, you probably just want to load the migration library alongside the 13 lib.
But, you may instead need to create your own migration lib specialized to the project by saving a PLA from 11, and then opening that PLA in 13 and extracting the library to a folder that you then further prune as necessary to load cleanly alongside the 13 library.
Here are two Wiki articles that may be of interest, if you have not seen them:
http://www.archicadwiki.com/LibraryMigration?highlight=%28migration%29
http://www.archicadwiki.com/The%20Magic%20of%20Parameter%20Transfer?highlight=%28migration%29
The last one, from Eric Bobrow, gives a method at the bottom for using parameter transfer to convert an 11 window to a 13 one. (The 11 windows and doors know nothing about partial structure display, introduced in 12, in case you need that.) However, there is a strong possibility that parameter transfer may not give exactly the intended result as GS changes some of the internal parameters at times. So, if you try this, check the result carefully.
Karl
AC 28 USA and earlier • macOS Sequoia 15.4, MacBook Pro M2 Max 12CPU/30GPU cores, 32GB
