0.42 is an early release because inbound bisection for firefox was broken, see bug 1199618.

Still there is some great improvements in there!

• Add an option to limit the persist folder size (bug 1195394)
• Help the user to use a config file (bug 1198866)
• Error message is not clear when looking for inbounds using changesets that are in the same push (bug 1195622)
• Remove the --http-cache-dir option (bug 1195085), prefer --persist and --persist-size-limit
• Changed the default good date of firefox 64 builds (bug 1194937)
• Disable the warning message about InsecurePlatformWarning for python <= 2.7.9 (bug 1199020)

Also we did a really nice work of making the code source easier and cleaner. Big thanks to MikeLing and Jonathan Pigree for their patches, reviews and testing contributions!