I have a closed “production” syncthing network and recently upgraded to 1.5.0. It was relatively painless, but I did have to go through some effort to disable crash reporting.
First of all, however useful it is to you, I am of the opinion that all phone-home systems should be opt-in. One machine said “this new setting is enabled by default but it appears you wouldn’t want it turned on so it’s off”, which was appreciated. I had assumed this appeared because I had anonymous usage reporting disabled, but on the other six machines after upgrading, crash reporting was enabled despite anonymous usage being disabled, so I’m not sure what the criteria is.
Next, I would recommend that the configuration option for it be located with anonymous usage reporting. People who are in a situation where one must be disabled are, more often than not, also in a situation where the other must also be disabled. One stop shopping for this would be nice.