Re: Support of older Emacs versions

[John Stoffel]

>>>>> "Stefan" == Stefan Monnier via General discussion of VM mail reader 
>>>>> <viewmail-info@nongnu.org> writes:

>>>> Thanks for your thoughts.  What version of emacs is in Ubuntu 20?
>>> My laptop (on Xubuntu 20.04.6) has emacs 26.3. (I don't use emacs, so I
>>> probably haven't done anything to update it past whatever comes with
>>> the distribution.)
>>> And if I install emacs on my personal Debian 11 server, I get 27.1
>> 
>> The "Long Term Support" versions of Ubuntu are every 2 years and have
>> 5 years of support.  Ubuntu 20.04 will be EOL in April of next year, so
>> that's 9 months, and maybe not worth the effort.  Ubuntu 22.04 (with emacs
>> 27) is still heavily used.  24.04 has recently come out, and has emacs 29.

> FWIW, so far in my cleanups I tried to remove only the compatibility
> code for Emacs<22.  Of course past experience suggests that I
> probably inadvertently broke compatibility with some more recent
> versions.  But I'd be surprised if it's not compatible with at least
> Emacs-24 and any incompatibility should be easy to fix once
> reported.

So far it's been working well.  

> As I mentioned earlier, the desire to preserve compatibility with XEmacs
> ensures or at least encourages to preserve compatibility with older
> Emacsen as well.

Not sure it's worth it... but since it takes work to remove stuff,
unless it's in the way I'd leave it too.

My current issues (which I need to open issues on) are

- When I hit space to view a message (which I have turned off by
default, showing only headers generally, I will get "Internal display
failed; use external viewer? (y or n) " which just slows things down
because now I have to answer 'n' since my external viewer blows up
too.  

- I'm seeing alot more messages when saving a group of messages to
another IMAP folder using "M N w" (I have 'w' bound to
vm-save-message-to-imap-folder) so I see a bunch more messages about
the various IMAP phases being done.  It's not a problem per-se, it's
just annoying that it's so chatty.