I can answer your question on Backdooring 11.4 into Maxthon3
If you have already downloaded the new 11.4 do This;
Using your windows explorer folder go to C:\WINDOWS\SYSWOW64\MACROMED\FLASH
In the flash folder copy this file.
NPSWF32_11_4_402_265.dll
then go to: C:\program Files (x86)\Maxthon3\Core\Webkit\Npplugins and paste the file there.
In the Npplugins folder delete the existing file NPSWF32.dll