When running "./syncthing --upgrade" on my 0.8.9 binary ( Linux 386 for example ) I get the error message "Current version v0.8.9 is newer than latest release v0.8.12. Not upgrading."
it’s a bug on versions <0.8.10, you have to upgrade manually this time. This also was in the release notes for 0.8.10
Ok , RTFM in my face !
or RTWFRN ( Read The Whole Fu*** Release Notes )