The most reliable source for specific older versions is the Mozilla Release Archive .
Addressed general crashes reported in previous 91.x builds. System Requirements for 91.8.0 ESR firefox 91.8.0 esr download
RHSA-2022:1287 - Security Advisory - Red Hat Customer Portal The most reliable source for specific older versions
MSI installers for Windows (both 32-bit and 64-bit) can be sourced from WingetGui or similar enterprise-focused repositories. Key Security & Stability Fixes firefox 91.8.0 esr download