To check the level of your Windows Client, go to the Main Toolbar / Help / About.
The WC level should be listed as: 12.7.871.x
You can install Patch 5 to your Windows Client that is at any level of B871.
Patch 5 is cumulative so the earlier Patches do not have to be applied.
SPECIAL INSTRUCTIONS:
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It will be best to reboot your PC just before beginning this upgrade and have no other applications running.
Make a copy of the BrightStor SRM folders before installing Patch 5.
This patch includes a new build of the Host Configuration Client and update
for the Scheduler Service as well as security updates. If you are running the SRM link Service (CA SRM
and CA Vantage Link Service) or the CA scheduler service (CA SRM and
CA Vantage Scheduler), please turn these services off before applying
patch 12.7.871.5 on the Windows Client 12.7.871 or B871 with prior patches installed.