@nuraman00
The firmware that Andy (EmpireAndy) posts on here is official firmware. Often times dealers are provided the newest firmware weeks or even months before Dahua posts it on their website for the public to access. I'd also point out that often Dahua packages firmware in a zip file with multiple copies that are used for different methods of updating which can be confusing for many since you might unzip a dozen or more different files. One is for updating via the Web UI, another for updating via special software, another (multiple or a single file) for updating via serial console interface, another for updating via SD card, etc. but they do not explicitly state which is which.
Just look in the UI menu to see what version you have now. It is right there under Setting>Information>Version.
Not exactly. In the past Dahua made multiple different types of the same version firmware for each camera which was also complicated and at times, confusing. They would have a PAL version and an NTSC version as well as both of those but one with Dahua logo, one without, and then often duplicates of those but with different languages. Dahua is moving toward making two (or three if you count China firmware) firmware for a camera that has the ability to select NTSC or PAL, select from many different languages. The only difference between the two will be if it has the Dahua logo or not. In your case, if yours currently is PAL and you can select NTSC then you need new firmware which has that choice.
The first post in this thread has what you want. You just have to choose if you want it with the Dahua logo or not.
As far as NTSC or PAL. These are just different video system types for different countries but these days, with IP cameras you can really use either one just fine. Depending on the resolution NTSC supports a higher frame rate but at a lower resolution. PAL has a slightly higher vertical resolution but a lower frame rate. For example in NTSC mode you might be able to choose 2560x1440 at 30 FPS but in PAL mode your choice would be 2688x1520 but at 25 FPS. So there are trade offs depending on which video standard you choose.