**Merged pull requests:**
- Fix Rails 6.1 related deprecation warnings [\#541](https://github.com/rpush/rpush/pull/541) ([dsantosmerino](https://github.com/dsantosmerino))
- GCM notification incorrectly mixes data into notification hashes [\#535](https://github.com/rpush/rpush/pull/535) ([mkon](https://github.com/mkon))
- handle priority in WNS [\#533](https://github.com/rpush/rpush/pull/533) ([Fivell](https://github.com/Fivell))
- Update development apns urls to match documentation [\#524](https://github.com/rpush/rpush/pull/524) ([jhottenstein](https://github.com/jhottenstein))
- Update README to remove incorrect info [\#523](https://github.com/rpush/rpush/pull/523) ([sharang-d](https://github.com/sharang-d))
- Fix and improve Travis setup [\#520](https://github.com/rpush/rpush/pull/520) ([aried3r](https://github.com/aried3r))
- Explicitly use Rails 6.0.0 [\#519](https://github.com/rpush/rpush/pull/519) ([jsantos](https://github.com/jsantos))
- Stale bot config change [\#515](https://github.com/rpush/rpush/pull/515) ([aried3r](https://github.com/aried3r))
- Add stale bot configuration. [\#514](https://github.com/rpush/rpush/pull/514) ([drn](https://github.com/drn))
- Correctly use feedback_enabled. [\#511](https://github.com/rpush/rpush/pull/511) ([kirbycool](https://github.com/kirbycool))
- Update apns_http2.rb [\#510](https://github.com/rpush/rpush/pull/510) ([mldoscar](https://github.com/mldoscar))
- Add `mutable_content` support for GCM [\#506](https://github.com/rpush/rpush/pull/506) ([hon3st](https://github.com/hon3st))
- Add support for critical alerts [\#502](https://github.com/rpush/rpush/pull/502) ([servn](https://github.com/servn))