* gossip: CPU performance improvements to memberlist gossip on very large clusters [[GH-5189](https://github.com/hashicorp/consul/pull/5189)]
* connect: clients are smarter about when they regenerate leaf certificates to improve performance and reliability [[GH-5091](https://github.com/hashicorp/consul/pull/5091)]
* api: Added a new `allow_write_http_from` configuration to set which CIDR network ranges can send non GET/HEAD/OPTIONS HTTP requests. Requests originating from other addresses will be denied. [[GH-4712](https://github.com/hashicorp/consul/issues/4712)]
* agent: Improve blocking queries for services that do not exist. [[GH-4810](https://github.com/hashicorp/consul/pull/4810)]