Update 2.1.x release branch for 2.1.4
This PR merges the changes from the following PRs onto the release/2.1.x branch to finalise the 2.1.4 release:
- #1363
- #1428
- #1441
- #1445
- #1463
- #1474
- #1480
- #1481
- #1484
- #1487
- #1488
- #1491
- #1492
- #1497
- #1499
- #1502
- #1503
- #1505
- #1508
- #1512
- #1517