In addition to enhancements and bug fixes, SSMS 17.7 comes with several exciting new features:
Support package scheduling in Azure-SSIS integration runtime.
Support for SSIS package scheduling in SQL Agent on SQL Managed instance. It is now possible to create SQL Agent jobs to execute SSIS packages on the managed instance.
Replication monitor now supports registering a listener for scenarios where publisher database and/or distributor database is part of Availability Group. So with this release of SSMS, you can monitor replication environments where publisher database and/or distribution database is part of Always On.
There are also several bugfixes that they call out.