Topic on Extension talk:UserAdmin/Flow

• In file "UserAdmin.php":

--- Uncomment lines 56 and 62 to enable "Specia:MassBlock" page

• In file "SpecialUserAdminPanel.class.php":

--- Change vfMsg() function to vfMessage()->plain() ..... Don't forget "->plain()" ant the end of function

-- Comment line 215 "$wgOut->includeJQuery()" because funtion was deprecated

• In file SpecialAddUser.class.php":

-- Comment line 161 " #$template = new UsercreateTemplate;"

-- Add "}" prior to the last one of the code

• In files "SpecialEditUser.class.php" and "SpecialPurgeUser.class.php":

--- Change vfMsg() function to vfMessage()->plain()

This worked for me