• Fixes smart spawning. A regression in 5.3.5 (due to a refactoring) made it so that Passenger only used the direct spawning method. This issue was mostly noticeable in the form of increased process spawning times between 5.3.4 and 5.3.5.
• Fixes Passenger Core and application processes staying on the Watchdog's OOM score (unkillable). Closes GH-2105.
• Fixes "mach_vm_map failed" warnings on macOS >= High Sierra. These warnings were harmless, but annoying. Closes GH-2101.
• Fixes passenger-config compile-agent compilation with optimizations. The optimization flags were not properly passed to the compiler.
• Fixes a crash that could occur when HTTP clients send a chunked transfer-encoding body containing a chunk larger than 429496729 bytes.
• Improves detection of the system Apache's include headers on macOS High Sierra and later.
• Fixes RVM gemset detection on RVM 1.29.
• No longer supplies precompiled Ruby extensions for Ruby 1.9.3 and 2.0.0. When running Ruby 1.9.3 and 2.0.0, Passenger will attempt to compile from source instead.