Unable to upgrade S170 WSA

[sojourncso]

Hello,

On S170 WSA I'm running the AsyncOS 7.7.0-760 however I see two upgrades are available:

Async OS7.7.0 build 761 upgrade for Web, 2014-10-01

Async OS8.0.6 build 119 upgrade for Web, 2014-10.27, is a release available for General Deployment

Any upgrade file I chose, I'm getting the below message, anyone can help?

Error during upgrade

The following errors occurred during upgrade:

Upgrade image is invalid. Please check settings and try again.
Upgrade exited without success.

Please attempt the upgrade again after clearing the error.

Thank you,

George