After upgrading Desktop and Laptop Option to 9.7 new files backed up from older client versions via BOI cannot be restored.

Problem

After upgrading Desktop and Laptop Option to 9.7 new files backed up from older client versions in BOI mode cannot be restored. 
The restore operation fails in the DLO Admin console, Web restores and DLO clients.
This issue affects any version of DLO Agent prior to 9.7 backing up to an upgraded DLO 9.7 Server when Dedupe is enabled and client is backing up in BOI mode.

Files backed up to from DLO Agents Prior to the server being upgraded to DLO 9.7 can be restored successfully.
 

Error Message

Error reading source file.  Error: Failed to open the file

Cause

The backward compatibility issue on clients is due to the upgraded Apache version in DLO 9.7.
The latest versions of Apache are not properly handling the encoded URL which is the cause of this failure.
 

Solution

Clients should be upgraded to DLO 9.7 as soon as possible. 
 

WORKAROUND:

There are two possible workarounds available:

OPTION 1:
It is recommended to Disable Dedupe in all profiles until all the DLO Agents can be upgraded to 9.7.

Once the clients are upgraded to 9.7, re-enable the dedupe option for all the profiles which had it enabled beforehand.

Note: After upgrading both server and clients to version 9.7, if file restore is still failing with the same error, then AIC (Automatic Integrity Checker) will resolve this DLO issue.
Automatic Integrity Check will automatically flag files that were backed up but cannot be restored and will trigger the agent to back them up again.

OPTION 2:

Temporarily stop the client backups

Disable all the Desktop Agents from Global Settings Option in the DLO Admin console as shown in below screenshot.

After the upgrade of all the Desktop Agents has been performed, return to the DLO Admin console and uncheck this option; to re-enable the backup of all the desktop agents.

Note: Disabling Agents can also be done before or after a DLO Server upgrade.