Finally, a last note: this fix doesn’t cover the case of using admin.example.com for your TXP admin side. I have yet to try that kind of install and figure out which will be, in that case, the best fix for the issue.

I guess quite simple as your way:

Redirect 301 /textpattern http://admin.blabla.ext/

mod_alias on Apache webservers is needed.

it should be

Redirect 301 /textpattern http://admin.blabla.ext

without the trailing slash – otherwise I had issues with Twitter’s oauth.

The Apache Redirect statement uses mod_alias rather than mod_rewrite. Some hosts do not allow mod_rewrite but mode_alias is a base module so Redirect should work even if mod_rewrite is not allowed.

Of course, because it isn’t using mod_rewrite, it is correct to place it outside of the <IfModule mod_rewrite.c> section (if present).

Some other webservers than Apache also provide simple redirect facilities (or even more powerful mod_rewrite-like ones) so this redirect mechanism should not be limited to Apache servers — only the implementation would differ.