SharePoint 2013: Workflow not working after installing August 2014 PU

Problem

After installing the August 2014 public updates to a SharePoint 2013 farm, some users reported that when they clicked on the Workflows link for a list or library item, they were navigated to the usual "Sorry..." page rather than the Workflows page.  A workflow designer also reported that she could not longer create 2013 workflows.  Curiously, 2010 workflows (legacy workflows migrated from 2010) continued to work and 2010 workflows could still be created in SharePoint Designer 2013.

Solution

1. Install  hotfix KB2880963, per the Microsoft TechNet article, Install a software update (SharePoint 2013). 
2. On the application server hosting Workflow Manager 2013, stop and restart these services:
1. Service Bus Gateway
2. Service Bus Message Broker
3. Workflow Manager Backend
3. Lastly, restart IIS on the WFEs.

References

• Workflow not working after installing Service Pack 1 and patches
• Update 2880963 for SharePoint Server 2013: May 13, 2014
• Workflow not working after installing Service Pack 1for SharePoint 2013
• The Magic of Get-SPProduct -Local
• Deploy software updates for SharePoint 2013
• Install a software update (SharePoint 2013)

Notes

• After installing this hotfix on all of the SharePoint 2013 servers, you may find that running the SharePoint Products Configuration Wizard returns an error:

  Error: Some farm products and patches were not detected on this or other servers. If products or patches are missing locally...

  If this occurs, execute Get-SPProduct -Local on each of the machines identified in the error message.  It may take several minutes for this command to finish.
• In Solution Step 2), above, I mention restarting workflow services.  It's not clear to me whether all of them need to be restarted, one or more of them, or maybe just restarting IIS, or some other combination of these.  Whichever the case may be, this is the combination I did to recover from experiencing an error clicking on Workflows for a list item, after installing the hotfix.  This approach worked for resolving this problem on both my development and production farms.