We're ready to start testing for 1.9.1.Final release. The aim is to release tomorrow.

As usual the testing spreadsheet is:
https://docs.google.com/spreadsheets/d/1uK46z0zQ1bkZi8cQxxF9czQPZ5NPd1jF9R3j-TNV7VY

Build the 1.9.x branch, not master, for testing. For any fixes send PR to both 1.9.x and master. If you discover any bugs during testing it's only a priority to fix if it's a regression, otherwise set fix version to 1.9.2.