Apr 19 2020
As a workaround, you can use a Lua module to decode the HTML.
Jun 11 2019
Sep 29 2017
I've asked at Wikipedia:Bot requests if anyone can help fix those particular errors.
Sep 1 2017
Aug 10 2017
Anything in the signature that causes Lint errors (Special:LintErrors) such as
Self-closed tags Misnested tags Missing end tag Obsolete HTML tags Stripped tags
Should mean that the custom signature does not get used.
May 1 2017
If custom signature contains deprecated self-closed HTML tags (or even just deprecated HTML tags) then mediawiki should ignore the custom signature and just use the default one.