If you are getting all attachment filenames in lowercase in Domino 12.02 then that is because there is an option to normalize attachment filenames that if I’m guessing enabled by default in some fixpacks.
The default behavior is changed in FP6 back to how it was before
SPR# MDLSDCSMFV – Programmability – LotusScript – Attachments – Fixed an issue where the internal attachment filenames were being changed to lowercase/half pitch to fix an issue in TMAICWHDAY. This was resulting in applications that used LotusScript EmbeddedObjects.Name property to show attachment names in lowercase/half pitch – note that EmbeddedOjbect.Source property contains the user friendly name. To fix this, the fix for TMAICWHDAY is now off by default – set AttachNamesNormalize=1 to enable the fix for TMAICWHDAY. This regression was introduced in 11.0.1 FP9, 12.0.2 FP4 and 14.0 FP2.
Fixlist Entry
https://ds_infolib.hcltechsw.com/ldd/fixlist.nsf/8ed1b46cfdba8957852570c90054623b/d01bc51222e6b8f985258c440048487b?OpenDocument
Original Blogpost