The current plan is that Firefox 57 will only support web extensions. Your add-on is not a web extension yet as far as I can see, so you should consider remaking your add-on. The Firefox 57 release is planned for 28th November 2017.
Already for Firefox 53 (planned release: 18th April 2017) it is planned to no longer accept other new add-on submissions than web extensions on AMO (addons.mozilla.org). Old extensions can however still be updated.
The good message is that one should be able to use your web extensions add-on in all mayor browsers. That's the idea behind web extensions.
Note that you can use so-called hybrid extensions for switching to WebExtensions.
Note that all dates are estimates and may be changed.
The current plan is that Firefox 57 will only support web extensions. Your add-on is not a web extension yet as far as I can see, so you should consider remaking your add-on. The Firefox 57 release is planned for 28th November 2017. Already for Firefox 53 (planned release: 18th April 2017) it is planned to no longer accept other new add-on submissions than web extensions on AMO (addons.mozilla.org). Old extensions can however still be updated. The good message is that one should be able to use your web extensions add-on in all mayor browsers. That's the idea behind web extensions. Note that you can use so-called hybrid extensions for switching to WebExtensions.
Note that all dates are estimates and may be changed.
German source: https://www.soeren-hentzschel.at/firefox/firefox-57-mit-exklusiver-webextension-unterstuetzung/ Original source: https://blog.mozilla.org/addons/2016/11/23/add-ons-in-2017/