As per github release comments:

Fixes:

Resolves some scenarios that caused calendar and contact sync to crash, unnecessarily stopping email sync.

You can now add Instagram handles to your email signatures (Thanks @piotrzarycki!)

When switching layout modes, Mailspring clears the selection to avoid an immediate mark-as-read

Github sources: https://github.com/Foundry376/Mailspring

(Tarball: https://github.com/Foundry376/Mailspring/archive/1.7.2.tar.gz )