go into saft folder open the content of the app - resources - saft.bundle and again view the content
there u'll find info.plist
at the end is something like
<key>SaftSupportedSafariBuild</key>
<array>
<string>5523.10.6</string>
<string>5523.10</string>
</array>
just add the string
<string>5523.15</string>
and you'll be able to start saft again
greetings