Merge pull request #2513 from Oldiesmann/release-2.1

! Minor fixes
I iz need to insert...

Signed-off-by: Antes <antes@simplemachines.org>
Merge pull request #2519 from Antes/upgrade_patch

Typo at upgrade sql(s)
! Fix error handling on XML preview

It totally did not work.

Signed-off-by: John Rayes <live627@gmail.com>
Merge pull request #2522 from live627/dev

! Fix error handling on XML preview