Firstly, an apology. It turns out version 1.5.5 was bad, as it was built of the wrong branch! This release has been withdrawn.
This is mostly the same as what was intended for version 1.5.5 with the addition of one tiny fix.
This is a major new version with many new things. It’s been running on our apps for about a month now and has been fine.
Lastly, what if you did install version 1.5.5? Basically, treat this as an early upgrade to version 1.6.0. Please upgrade to the real version 1.6.0 and accept our apologies for this.