We're planning to release an Apple Silicon native port of Terragen 4 this year.
From what I've read, macOS 27 will continue to include Rosetta 2, enabling it to run Intel versions of software. As far as I'm aware, what's ending in macOS 27 is not support for Intel software but support for Intel CPUs, so Terragen 4 should continue to work just fine on your M5 with macOS 27. Support for Intel software is planned to end with macOS 28, due next year. We plan to release Apple Silicon native Terragen before then.
According to Apple Support (
https://support.apple.com/en-us/102527), "Rosetta is currently available for any Mac with Apple silicon, and it will remain available through the forthcoming macOS 27 — the next major macOS release. Starting with computers using macOS 28, Rosetta functionality will be available only for certain older, unmaintained games that rely on Intel-based frameworks." This information was published February 16, 2026.
If this changes, please let us know and we'll adjust our roadmap to make this a priority.