I suppose you bought your device in China or at a Chinese reseller. You cannot install the I version on these devices straightaway, since this is blocked by Meizu. There is a hack/workaround which you can find in the General Chat section, but be careful. If you don’t want to try this, you have to stick to A firmwares.
Hey here is a solution.
I bought my Meizu from a Chinese reseller too and was unable to update. When I downloaded the .zip file the only option I had was to unzip or view contents. I think the reason for this was because of the old version of Flyme did not have the feature to install a update via the .zip file.
So what you do is download the latest version and I assume you are using the Chinese version of the device so download the Flyme OS 4.5.4A if you do have the Chinese version of the device.
Just download the .zip file which will be update.zip I believe and leave the .zip file in the root directory on your phone storage.
Now reboot the phone into recovery with Volume Up + Power, which will lead you to the recovery.
Once you do that it will automatically detect the update file in the root directory and ask you to update with a box that you can check to wipe user data.
Since you running a old firmware I would recommend you wipe data too before you made a backup of files if you want to. Now it will update and from now on you can just update any future updates via the documents app because these latest firmware allows to update this way.
@Blackthunder81 read the F.A.Q. or use the search function of this forum, before you post! This question has been asked a 10000000000000 times, or so.
Only international devices that have the model code “H” in the end, are able to install the international version. Have a look at the F.A.Q. for more information about the Firmware differences.