RingCentral App minimum OS requirements:
Windows 10 and above and Mac 11 (Big Sur) and above
Release 26.4.20 requires macOS 12 (Monterey) or later. Note: the minimum rises to macOS 13 (Ventura) after Release 27.1.10 (January 2027)
— if updating now, go straight to macOS 13 to avoid updating twice