Hello
1- As you mentioned , i did not see v 5.3.10 . I think you have to contact Cisco TAC , for sure they have answer for that.Ask about what is the replacement if there is no v5.3.10 because as per document only
v5.3.10>v5.3.11>5.3.12.
2-you have to make sure that you hardware support v5.3.11/12.
http://www.cisco.com/c/en/us/td/docs/video/digital_media_systems/5_x/5_3/showandshare/upgrade/hardware/SNS_5-3-10_Rel_Notes.html#76179
3- if you are unable to get software v5.3.10 . you can do the following.
A- download the new image for v5.3.11 or v5.3.12
B-burn it on CD as iso image
C-Take a backup for existing show and share contents .
D-Do a fresh installation for 5.3.12 , then do restore.
Thanks
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