The v27.11.2020 release was designed for the transition period between older and newer architectures:
Plugins were optimized for high-pixel-density displays, ensuring graphics remained sharp when scaled. Waves 12 Complete v27.11.2020
Improved GPU usage for rendering plugin interfaces, which offloaded some processing from the CPU. 3. Core Plugin Categories Included The v27
Waves transitioned to as the primary management tool. Core Plugin Categories Included Waves transitioned to as
H-Delay, Abbey Road Chambers, Renaissance Verb, Manny Marroquin Delay Waves Tune Real-Time, Vocal Rider, Waves Harmony, DeEsser Modeling J37 Tape, Kramer Master Tape, Abbey Road TG12345 4. Compatibility and System Requirements
For many users, V12 represents a "stable" baseline. If you are running an older machine or a specific OS (like macOS Catalina or early Big Sur) where newer V14/V15 plugins might be buggy or unsupported, the v27.11.2020 build is often cited as a highly reliable version for professional sessions.