Lotus Domino 8.5.3 for i is available from your local authorized Lotus reseller, your IBM representative or IBM Business Partner. You can also download the Trial Web kit and try Domino 8.5 for 90 days!
A GA Hot Fix is available for Domino 8.5; see these Technotes for more information:
Attention LEI clients
Lotus Enterprise Integrator (LEI) Version 8.5. is required for use with the same version of Domino 8.5.
Important note for Language Pack users
If you currently use or need a non-English version of Domino, do not install the current maintenance release until the corresponding language packs are also available. When you upgrade a Domino server that has language parts installed, the upgrade process replaces all Domino language parts with the corresponding English version. Language packs are typically available 30 to 60 days after the English version.
Compatibility with other Lotus software
For the latest information about software compatibility for maintenance releases of Domino 8 and other Lotus software products, see the Lotus Software for IBM i operating system Compatibility Guide (PDF, 212KB).