The phrase signifies the stage in software development where an updated version of the iOS operating system, specifically version 18, is in the process of being readied for release. This involves compiling code, conducting rigorous testing, and finalizing the features intended for the end-user. This stage precedes the final distribution to devices.
This phase is vital because it determines the stability and functionality of the new software. The effectiveness of this step directly influences the user experience following the update. Historically, such preparatory stages have been crucial in mitigating widespread issues and ensuring a smoother transition to newer operating system versions.