Personally I use the ESR release. It is designed for those that look for stability and continuity, particularly business users that do not necessarily need or even want the latest and greatest flying monkeys graphic but value that the thing is updated for security and stability regularly (like Thunderbird has been for the last 10 years really)

The release version is in my opinion the bleeding edge. Every new feature complete or not appears to be released in it and it is of questionable stability and quality I feel. Personally I see it more like a late beta that a release, but the folk making Thunderbird just had to have the same release schedule as Firefox. I don't really understand why as Firefox continues to loose users.

Personally I removed Norton from all of my systems more than 20 years ago as my children disabled the "resource stealer" every chance they got. Peter Norton made a great product, two actually. Symantec, not so much. Gen Digital is an unproven factor that does not inspire as it is little more than a renamed Symantec merged with Avast.

As you can see here Norton is not offering good advice as to what is "up to date" but that does not stop the software messing with folk and suggesting they make an irrevocable move to release as the profile per install applies top changing from ESR to release going back when your add-ons don't work is not really an option. https://support.mozilla.org/en-US/kb/dedicated-profile-thunderbird-installation

Thunderbird has a perfectly functional update process that checks for updates and automatically downloads them. It balances server loads and user risk with the process as updates to existing users are always done after a new version is release on the website. Allowing a window for grievous issues missed in testing to appear to new users before millions of existing users even see the update. Then when updates are enabled the updates are trickle fed beginning with 10% of those checking for an update and those figures are increased as the teams level of confidence in the release rise. While I have issues about the quality of release in general, there is no effort spared to mitigate user risk as much as possible. Saying that I know there is always risk, but the team do try and minimize it, especially for those on ESR, only commencing those updates after the release version is completed.

Several years ago the Thunderbird team paused updates when a serious bug was found in the release version. However antivirus software offered folk the advice to download and install the new release and flooded this forum with complaints that were meaning data-loss for many users all because their antivirus product could not stick to malware detection and prevention. It was Thunderbird everyone was critical of, not the product that offered them a process to corrupt their own data.

You get one time a year where you can change over with impunity Release to ESR. While release and ESR are actually the same version. However due to update cycles in practice this is much less than a month, perhaps even only a couple of days as ESR "updates" are generally only enabled when the next release occurs.

Thank you, Matt. You helped me answer my question to myself about whether I should move away from the esr channel for updates. (NO) Your reply raises an unrelated question that I have been wondering about, when you mentioned your removal of Norton from your systems. I have recently read some opinions that no additional security is needed for Windows systems beyond what Microsoft provides. Is that your opinion also, or do you use some other antivirus/security software?