Localization has been fixed, so the next version of Lightning should have a language pack.
Note, it was mostly localization issues, especially on Lightning, that prevented 2.42 and various other versions from being released.
Thank you. I'm happy with a localized 4.0.x, its use typically is restricted to replying as expected to rare, Microsoft-based invitations, but wouldn't have minded to look at localizing an upgrade to 4.7.x by using several translated input files in two of the XPI directories.
IIRCR the article in German suggested some "quick & dirty" update or compatibility issue, an/or solution, which was solved by herr Kohl with a matching German version, but I should have replied to that series of article back then.
Presumably a language pack is a superiour solution anyway, at leat compared to having to compile XPIs for several of the available OS/2 languages.