currently having hDLP 9.1 Patch 1. upgrading hDLP ePo extension to hDLP 9.2. Will it be smoothly working with hDLP 188.8.131.52 client?
No, you have to use same extension with same version onclient as well server. In client systems it might comes process utilizationissue.
As long as you ensure backwards compatibility is enabled (tools, options, general), then it will be able to enforce policies on the older clients.