After this ticket, the enableMajorityReadConcern:false server parameter will be available in 4.0. This parameter should be recommended for replica sets containing arbiters. Single replica set transactions are supported with enableMajorityReadConcern:false, but change streams are not yet supported.
The enableMajorityReadConcern:false option exists on 3.6, to allow the server to avoid holding on to all history since the majority commit point. We would like to add this option on 4.0 to address pain due to commit point lag in replica sets with arbiters.
This work should include adding the enableMajorityReadConcern:false Evergreen variant to 4.0, which was introduced in
SERVER-36083. This variant should include all of transactions tests on 4.0.