You can find the latest nightly 2.53.x build here.
The 2.53.x language packs for the nightly build are available at langpacks.
These builds and language packs are provided by Bill Gianopoulos.
The major 2.53.x defects are tracked in Bug 1688498.
Nightly defects in comm-central are tracked in Bug 1452448.
As with all unofficial releases be careful and have a full backup of your profile ready. Downgrading to prior versions was never and will not be supported.