Updated to 2.3.8.118 this morning. I did an additional reboot to purge logs after a short while. The free memory is as low after a couple of hours as it previously was after a month of uptime.
I'll try another reboot a bit later. Updating the hub these days feels like:
I would not consider 300 low.
Seems like the issues all got solved in 2.3.7 for me. I dont even look at it anymore.
My guess would be, it just downloaded the latest Diagnostics tool. This sort of dip/recovery pattern is typical for a Diagnostics tool update.
I've had my hubs run fine at as low as 150mb, so for me 300 would be bonus memory territory... 
There isn't a specific memory level that is required - I've run my hubs at 150 and lower w/out issues, others have run into issues when <300. Unless and until you have issues w/automations/devices then you really don't need to worry too much about your memory level.
agreed when i had my heavily loaded c7 . it would work ok down to about 120 meg.. the first thing you will see when too low at least in my case was zigbee offline..
Perhaps my second reboot to clear the logs (5 or 10 mins following update) was before that diagnostic tool updated. It has indeed jumped back up to 415MB now.
Fair enough. The concern was that I updated at 310 MB after two weeks uptime and it was below that 2 hours after update but it's looking better now.
My life must be fairly empty to be posting about a number being lower than desirable from a PCB 
As many hands go up in the room...
The problem I see with the low memory, is when it trashes Zigbee, Zigbee may come back with a PAN ID change, and that typically kills many batteries in my sensors costing me battery dollars, as they hunt for a new network. This isn't always the case but it depends on how bad the crash is.
Besides my automations start to run slowly.
I've had to reinstate my auto reboot rule for below 250k
Download the Hubitat app
