Is 15 the maximum length of a librecalc-created password?

Using librecalc I can open Excel files that have a password exceeding 15 characters. However, when I use librecalc to save the file and change the password, it appears that the maximum length is 15. I discovered this through trial and error. If indeed this is the maximum length, it is too short for my circumstance. Can anyone verify that 15 is indeed the limit? If it is longer, then I may need to reinstall librecalc.

Yes, it is the limit for MS formats (not for native formats though) - see tdf#97086.