Communication between Couchbase Lite and Sync Gateway is secured using SSL/TLS, relying on a Public Key Infrastructure with X.509 certificates to establish the server's identity, which may be compromised or self-signed, posing potential security threats. To address these issues, Couchbase Lite supports certificate pinning, a technique that allows applications to verify a server's identity using a pre-configured certificate, mitigating risks associated with third-party Certificate Authorities and self-signed certificates. Certificate pinning is implemented by bundling the server's certificate within the client application, removing reliance on external verification. In Couchbase Lite version 1.4, certificate pinning is available for iOS, with plans for broader platform support in the upcoming 2.0 release. Developers are advised to update applications with new certificates upon expiration, as updates may require additional steps such as App Store reviews. The post provides guidance on implementing certificate pinning in iOS applications and emphasizes the importance of managing certificate lifecycles to maintain secure communication.