improved_mboxlist_sort has no effect on 3.8

[jcdelepine]

Hello,

In a mixed murder configuration with most backends and mupdate still in version 3.2, the 3.8 backends can't synchronise with mupdate.
See issue #4946

One solution is to use improved_mboxlist_sort to change the sort comparator.
It works fine on 3.2 to force the new comparator.
But it doesn't works on 3.8 in order to force the old one.

Order on 3.2, with improved_mboxlist_sort off :
user.test2.a-b
user.test2.a.b

Order on 3.8 replica, with improved_mboxlist_sort off :
"user.test2.a.b"
"user.test2.a-b"

If this option is not too much work it could be useful for large murder upgrade.
One can include new updated backends with the same improved_mboxlist_sort as the mupdate server and make the sort change later on an updated cluster.

Sincerly,
Jean Charles Delépine

[dilyanpalauzov]

improved_mboxlist_sort does nothing in 3.8, but is not yet removed from the documentation - #4559.