On Tue, 2 Aug 2016, David L. Johnson wrote:
These are being created since the files were edited by the new version of LyX you installed, which uses a newer format. LyX then auto-saves them in the old format so that you can edit it, if you need to, with an older version of LyX. This seems to be a reasonable thing to do at the start of a new format, and will not occur when you edit files using LyX-2.2 that are already in the new format.
David, Thanks for the clarification. I don't recall seeing these files when previous versions (from 1.0 on) were upgraded. Regards, Rich
