It was quite confusing for me before I figured out that the User Defined Language (UDL) in Notepad++ have 2 different versions i.e. v1 and v2 which are not compatible with each other as well as the UDL XML file used for import/export.
In Notepad++, there is a feature which you can define your own language for syntax highlighting i.e. User Defined Language (UDL). UDL can be exported and imported with XML file. There are a bunch of UDL files available here (include 2 files for ABAP) so you don't need to define everything by yourself.
However, there are two versions of UDL and they are not compatible with each other. So before import a new UDL file, you should check the version first. Here is how to check: