Yup that's true, the new and much expected Cumulative Update 4 for Workflow Manager is finally here.
Yes, it will be possible now get over that always troubling issue of the expired certificates, or the so enraging pain of the Restore-WFScope don't do all the work when you have associated workflows or even the always present fear of my Certificates expiring without I even receive any alert.
In the next days I will try to post here some of the new cool stuff that was included in this new update, in the meantime go get it on the below link:
After some testing and reading the blog post that came out from the PG itself, it seems that you will need to install first the WFM CU3 before install the WFM CU4, so be careful with that since that requirement is not specifically referred in the KB announcing the WFM CU4.
For more information check the below articles:
Hope that Helps