We published the new v.12.1 on 11/16/2017 afternoon without any issues from the Mozilla auto-check editorial system. But in 18 hours the extension was removed by Mozilla AMO team based on some issues which have not been explained anywhere in the Mozilla documentation. The new version 12.4 has been just published. Please install the new version.

The new updated ImTranslator version 12.1 has just been published.
THIS VERSION IS COMPATIBLE ONLY WITH FIREFOX 57 or HIGHER
Legacy version of ImTranslator is here:
https://addons.vaultpit.io/en-US/firefox/addon/imtranslator/versions/

Original text can be played in ImTranslator Application