After IBM BPM 7511 upgrade old task started from deactivated snapshot failing

Recently we have upgraded to IBM BPM 7511 versino from 7510 and after upgrade we monitored that instances are failing for all the sanpshots which are deactivated. That means if you have started an instance from snpashot 1.0 and then deactivated that snpashot and instance migration was also not performed. All the running instances having referance to snpashot 1.0 will fail.

After investigation we found that it is due to new properties added in 7511.
Business Process Manager Version 7.5.1 Fix Pack 1 added the following new properties:

1. block-deactivated-snapshot-favorite-progression block-deactivated-snapshot-task-progression
2. 
   

These two properties exists in the "99Local.xml" configuration file, are defined, by default, with value "True". This default value for these properties will stop in-flight tasks on the deactivated snapshot.

If you want to process or excute in-flight tasks or instances on deactivated snapshots, you have to change this property to "False"

Note: You do not want to modify the 99Local.xml configuration file directly. Instead, use the 100Custom.xml file to override the values using following steps

To execute these in-flight tasks, complete the following steps: 

1) Locate the 100Custom.xml file.

2) Add the following XML code to the file:

 <properties>
   <server merge="mergeChildren">
     <block-deactivated-snapshot-favorite-progression merge="replace">false
     </block-deactivated-snapshot-favorite-progression>
     <block-deactivated-snapshot-task-progression merge="replace">false
     </block-deactivated-snapshot-task-progression>
   </server>
 </properties>

3) Restart the server.