Should we drop macOS 10.14 for the ChimeraX 1.5 release?

[Tom Goddard]

We have one trouble with macOS 10.14 where distribution would be simplified if we required macOS 10.15. The dmg file format that the Mac ChimeraX is distributed in has improved compression (LZMA) in macOS 10.15 over 10.14 (zlib) resulting in large file size reduction (400 MB down to 250 MB).

We could provide a separate macOS 10.14 Intel Mac dmg. The Safari browser reports when the OS is 10.14 so we can present that dmg when appropriate.

We plan to have universal, arm and intel Mac builds for ChimeraX 1.5. We could make just the Intel dmg use 10.14 compression.

When a newer dmg with LZMA compression is opened on macOS 10.14 it gives a somewhat cryptic error message that the compression format is not supported. So we want to avoid macOS 10.14 users getting dmg files with newer compression.

Our download page says that ChimeraX 1.4 is the last release on macOS 10.14. So we have given fair warning if we decide to drop it.

We should see how many ChimeraX users are using macOS 10.14 by looking at our web server logs and possibly at the ChimeraX trac tickets.

[Tom Goddard]

It appears that 4.5% of ChimeraX 1.4 Mac downloads are on macOS 10.14. About 120 downloads per month of ChimeraX 1.4 on macOS 10.14 from unique IP addresses.

Sept 1-21, 2022 had 1765 ChimeraX 1.4 Mac downloads from unique IP addresses.
Of these 79 (4.5%) were from macOS 10.14.

watson$ cd ~goddard/cx_web_log
watson$ grep ChimeraX-1.4.dmg /usr/local/www/logs/plato-httpd/rbvi-production/rbvi-production-ssl_access_log > mac_1.4_sept_log
watson$ wc mac_1.4_sept_log 
   6060  142708 2172049 mac_1.4_sept_log
watson$ awk '{ print $1 }' mac_1.4_sept_log | sort | uniq | wc
   1765    1765   43975
watson$ grep ChimeraX-1.4.dmg /usr/local/www/logs/plato-httpd/rbvi-production/rbvi-production-ssl_access_log > mac_1.4_sept_log  C-c C-c
watson$ grep 10_14 mac_1.4_sept_log > mac10_14_cx1.4_sept_log
watson$ wc mac10_14_cx1.4_sept_log 
   279   6742 103678 mac10_14_cx1.4_sept_log
watson$ awk '{ print $1 }' mac10_14_cx1.4_sept_log | sort | uniq | wc
     79      79    1893

[Tom Goddard]

Decided we should keep support for macOS 10.14 for the ChimeraX 1.5 release. We will show just the universal Mac build on the download page unless macOS 10.14 is specified in the browser user agent in which case we will show the Intel Mac build. I changed the download page today to do that and tested on essex2 which is a macOS 10.14 machine. The Intel Mac distribution uses the old zlib dmg compression while the universal build uses LZMA compression to produce much smaller size (about 2/3 of the zlib compressed size).