Upgrade applied to staging, patch submitted for review. Best to merge it after 4.2.1 is out.
New security advisory published, patch updated accordingly and applied to Staging
New Jenkins LTS released, patch updated accordingly and applied to Staging, will apply it to Prod as soon as possible
Will also apply GC optimizations on Prod (they're enabled on Staging for quite some time and we haven't seen any issues there)
Patch applied to prduction along with G1 garbage collector and a full OS update