RNCryptor 4 is a complete rewrite of RNCryptor for Swift 2 with full bridging support to Objective-C. It has a streamlined API, simpler installation, and improved internals. It continues to use the v3 data format and is fully interoperable with other RNCryptor implementations.
For users desiring a fully Objective-C solution, v3 is still available. I don't currently plan to do significant new work on v3, but will consider it if there is strong interest. Going forward, I expect most OS X and iOS projects to be able to accept a mix of ObjC and Swift code. Objective-C continues to be a fully supported language in RNCryptor 4.
I plan to convert this to a final release in a week or so if no major issues are discovered.