Preparing for the new release, I just downloaded a backup file.
In looking at my backups folder, I noticed the size of the backup file got dramatically smaller as of the backup I saved on December 6th (2.2.4.153).
Yes, somewhere around 2.2.3 (I think--might be off by a minor release in one direction or the other), they reduced the default size of device event history, I think from 1000 down to 100 per attribute per device. They also made other platform stability improvements, some of which may (or may not) be related to the database. All things considered, but likely mostly due to that reduced history, most people's backup sizes decreased significantly after this. (There is a way to change the default as well as the per-device setting for this if you have any specific needs, by the way; the former has a "secret" URL and the latter is now on the device page.)
Big change in logging from 2.2.2 to 2.2.3
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