You mean creating XMP-files before opening in DPLv2 (or now v3)?
if so this stays the same, for now, DPL is read only at this moment for XMP’s. So no worries there.
See manual: “Allows the application to process and export your RAW images while using metadata previously stored in an XMP-format file alongside the input image (e.g., metadata created by a program such as Adobe Bridge).” It only reads them.
Indeed what Sigi said:
But one safety step more.
1 create a folder in every image folder called “Sidecare backup”
2 copy all sidecars in there per folder-content. (Now you have persevered/back upped the v2 sidecars in there latest state. )
3 install DPLV3 go to preferences and uncheck the "save settings in sidecar file (.dop) automaticlly)
and if you like you can uncheck “load settings…” in V2 to keep your V2 Database in effected from changing sidecars by V3.)
No your safe to fool around without changing your work.
(DPLv3 generates new/or modify sidecars in every folder you are entering and if it does your backed up one’s arn’t seen or touched when you select “safe settings…” after a wile so your save for returning to pre V3 state by oeverwriting the sidecars with your back upped ones if you need.)
(i do this for all my archived rawfiles creating a timestamp backup sidecars so when i am having a issue i just use this backup .)
And indeed select some test images copy them in a “testing v2 against v3” and you can open this folder in both to do some editing without enter-fearing because the changes are inside the databases not effecting the sidecars.
After done testing your DPLV3 delete the database and check the preferences according to your liking.
(you can preserve editing in two way’s;
1- turn on “save settings” to overwrite all sidecars all opend folders.
2 select your images your want generate some sidecars for and use : File => sidecars => export
This way you preserved your work on those when you delete the v3 Database.
And you have a fresh setup for migrating to v3.