You need to as get your addon signed. it will no longer install. See https://support.mozilla.org/en-US/kb/firefox-add-technology-modernizing?as=u&utm_source=inproduct
Thank you for reporting this! It appears that Firefox is currently experiencing an issue related to extensions. This is affecting all extensions, not just AdBlock. We're crossing our fingers for a quick fix! Here's a link with more information about the bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1548973
