Also, remove the obsolete protocol versions 2 and 3

and some further tidying up.

Squashed commit of the following:

commit 7b13b9f0
Author: Simon <simon@gb7fr.org.uk>
Date:   Sun Jan 29 19:01:33 2023 +0000

    SERVER_ID is bytes!

commit cee3bc76
Author: Simon <simon@gb7fr.org.uk>
Date:   Sun Jan 29 18:50:06 2023 +0000

    frog

commit 82432b9c
Author: Simon <simon@gb7fr.org.uk>
Date:   Sun Jan 29 18:49:53 2023 +0000

    fred

commit 6601573c
Author: Simon <simon@gb7fr.org.uk>
Date:   Sun Jan 29 18:39:08 2023 +0000

    Stringly

commit 28fa37f8
Author: Simon <simon@gb7fr.org.uk>
Date:   Sun Jan 29 18:30:37 2023 +0000

    self

commit 3e6d28d4
Author: Simon <simon@gb7fr.org.uk>
Date:   Sun Jan 29 18:23:42 2023 +0000

    Fix trace

commit a15901dc
Author: Simon <simon@gb7fr.org.uk>
Date:   Sun Jan 29 18:21:30 2023 +0000

    Tweak config file used in install script

commit 654ec135
Merge: f75ff26c d4e3922d
Author: Simon <simon@gb7fr.org.uk>
Date:   Sun Jan 29 17:48:22 2023 +0000

    Merge branch 'master' into testing

commit f75ff26c
Merge: c0b5216e 48339d31
Author: Simon <simon@gb7fr.org.uk>
Date:   Sun Jan 29 17:46:07 2023 +0000

    Merge branch 'master' into testing

commit c0b5216e
Author: Simon <simon@gb7fr.org.uk>
Date:   Sun Jan 29 11:04:45 2023 +0000

    more config work

commit c79ce055
Author: Simon <simon@gb7fr.org.uk>
Date:   Sun Jan 29 00:54:56 2023 +0000

    ib

commit 294a09c8
Author: Simon <simon@gb7fr.org.uk>
Date:   Sun Jan 29 00:50:36 2023 +0000

    Enable minimal config and tidy up global ACL

commit d1dc58d4
Author: Simon <simon@gb7fr.org.uk>
Date:   Sat Jan 28 23:12:41 2023 +0000

    Deprecate protocol versions 2 and 3