I've had my hub for just over 2 years and have a handful of rules and routines. I also use it as a basic home alarm system, mainly to notify us of intruders. Lately, I've noticed rules, routines, and HSM become corrupt whenever a new hub firmware is available. I didn't want to make this my hobby, I have plenty to occupy my time. Why can't I rely on my hub to do what I want it to, forever? After all, my phone doesn't quit working whenever an OS update is available.
What model hub do you have? I’ve never seen this on my C-5 (now largely idle except to work on driver changes) or my production C-7.
I understand that there are issues with the C-3 and C-4 because of the different underlying JVM (64 bit rather than 32 bit), and I believe that most C-3 and C-4 people are staying on an earlier release (2.2.3 or 2.2.4). There are some threads in the forum about that.
Nothing forces you to update firmware.
I am in the camp as you, I would prefer that it just worked and never required my attention. That’s pretty much the case now, but I don’t do anything sophisticated.
I believe that your observation above may simply be coincidence. The Hubitat team has been working on improving the reliability and uptime of the platform for quite some time. Unfortunately, there may still be a slow memory leak or two yet to be vanquished. Thus, my hypothesis is that your hub may be experiencing this slow performance degradation which culminates in the behavior you're experiencing. When it happens, and you investigate and correct the issue, coincidentally there is a new firmware version available.
If you want to keep your hub on an older firmware version, I would recommend a weekly automatic reboot of the hub at a predetermined time. There are some very simple ways to accomplish this, including using rule machine. Search the community and I am sure you'll find plenty of options.
On the other hand, keeping the hub's firmware up to date, may help with long-term reliability as the team really is finding and eliminating bugs in every release. Of course, they are also adding new features which may contain new bugs... So, it is a bit of a balancing act.
I have a C3, a C4, and a C7 hub, all running the latest 2.2.5.x firmware. This has been a pretty darn stable release for my home automation needs. However, as a tinkerer and developer, I will say that my hubs probably do get rebooted at least once every two weeks and thus I may not be the best source of data for how long a hub can run without experiencing degradation over long periods of time.
I tried 2.2.5.x and found a bunch of my rules and automations randomly stopped working. I deleted and recreated them which seemed to help but still not 100%. reliable along with some other Z-wave network issues that appeared. Ended up reverting back to 220.127.116.11 and I will happily stay here until I have a direct need to upgrade again. If it ain't broke, don't fix it. If you hub and network is performing perfectly, leave it as-is.
I have a C4.
Then, based on what I have seen from others in the forum, you are best staying on an earlier release. I believe that staff is working on getting the updates stable on the C-4.
If you see 2.2.5-specific issue, and 2.2.4 was stable, yes, please roll back to an earlier release. We test every version internally and then in a larger beta group, but we (obviously) don't catch everything. That's why diagnostics tool has a revert feature. If 2.2.4 is no longer on the hub because of several 2.2.5 updates, it can be downloaded directly using http://your.hubs.ip.address/hub/advanced/download224 endpoint. Give it couple of minutes to do its work, and it will show a simple success/failure text status message when done.
We have had some issues reported, and yes, fixes/feedback is being incorporated in 2.2.6 that's currently in works. I don't believe there's anything C4-specific there, though. As for earlier versions, there's no real sunset policy on them - if a version works today, it will continue to work tomorrow.