PUBLIC MARKS from decembre with tag downgrade

Once a profile has been used with Firefox 55 (or later), it should not be used with previous versions of Firefox. IndexedDB, the (DOM) Cache API, Service Workers, and the asm.js cache will all fail to operate, generating confusing errors and causing portions of Firefox and some websites to break. The profile can be made operable again in older versions of Firefox by using the profile "refresh" mechanism.

Firefox Setup 21.0 FR - (OFFICIAL RELEASE 10 AVRIL 2013)

FIR OLD VERSION (candidate ) - FR - 20.1 MAI 2013