Files with 2015 extension may be related to various file types saved in the year 2015.
2015 file extension - Any data file created in 2015
What is 2015 file? How to open 2015 files?
File extension 2015 is most likely related to data files created or backed up in 2015.
Also may include some kind of financial, tax preparation, business, calendar, schedule, accounting data.
If the file name contains two extensions, try to rename the file to the original extension (delete the 2015 extension from the file name).
This 2015 file type entry was marked as obsolete and no longer supported file format.
This type of file is no longer actively used and is most likely obsolete. This is typically the case for system files in old operating systems, file types from long discontinued software, or previous versions of certain file types (like documents, projects etc.) that were replaced in higher versions of their original programs.
