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On February 3, 2012, Salesforce will begin rolling out the Spring ’12 Release with an undocumented change to how the Case Thread ID is formulated. The Case Thread ID is a standard unique ID that Email to Case Premium uses to match inbound emails with existing Cases when appropriate. You may need to make changes within your email templates, and those instructions are listed below. If no action is taken, there is a risk that inbound emails will always create new Cases rather than updating existing Cases when appropriate.
Starting in the Spring ’12 release, the output from the {!Case.Thread_Id} merge field will change.
For example:
As of one day prior to the release of Spring ’12, this change remains undocumented. Therefore, Email to Case Premium has not been updated to accommodate this new format.
For Text or HTML/Custom type Email Templates used for Cases:
Replace the {!Case.Thread_Id} merge field with {!Case.E2CP__Case_Thread_Id__c} in every email template you use for Cases.
Do this in both the Subject and in the Text/HTML body of your email. Be sure to update templates that are used when sending new Case Auto-Responses, updates to existing Cases, and Case Closure workflow, if applicable.
Our approach would be to Navigate to Your Name | Setup | Communication Templates | Email Templates and open each template listed as Text, HTML or Custom in the Type column. You can use your browser’s “Find” function to search for {!Case.Thread_Id} and replace it with {!Case.E2CP__Case_Thread_Id__c}
For Visualforce Email Templates used for Cases:
If you are using Visualforce templates exclusively, you are already using the correct field because the problematic field can’t exist in a Visualforce template. Therefore, no changes are necessary.
See the Knowledge Base article on this topic for more details.
Q. Why wasn’t more noticed provided?
A. We regret that we could not provide more notice but the developer community received no official advanced notice. As of 1 day before the release of Spring ’12 this change remained undocumented and therefore Email to Case Premium could not been updated in advance to accommodate this new format.
Q. Are there any known caveats or limitations?
A. No, there are no known caveats or limitations.
Q. When should I update my email templates?
A. You can update them immediately and need not wait for your instance/organization to be upgraded to Spring ’12. The {!Case.E2CP__Case_Thread_Id__c} is backwards compatible.
Q. What is the impact of using the {!Case.Thread_Id} merge field after Spring ’12 is released in my instance/organization.
A. Immediately after your instance/organization is upgraded to Spring ’12, the output of {!Case.Thread_Id} will change. Email to Case Premium will not immediately recognize this new format, but we will release an update in the near future that does. If you continue to use {!Case.Thread_Id}, replies to emails sent from Salesforce after your organization is running Spring ’12 will not update existing cases but instead will created new cases.
Q. Can I simply merge the duplicate cases using Case Merge Premium?
A. Yes, you can, but that is certainly not a long term strategy and would be rather tedious.
Q. Do I need to update every email template, or just those that are used when sending emails from the New Comment page?
A. We recommend you update every single email template, including those that are inactive.
Q. I use all Visualforce templates and noticed they already have the recommended {!Case.E2CP__Case_Thread_Id__c} field in them. Is this expected?
A. Yes, Visualforce templates cannot use the problematic {!Case.Thread_Id} field, and will always have the recommended field for solving this issue. You do not need to make any changes to Visualforce templates.