Quote:Do I need to upgrade ?
It is your decision not to upgrade with all consequences. We only support the current version (1.4.3.4 is nearly five years old!). So even if there was a bug you will not get a fix without upgrading.
It is recommended to frequently upgrade as with any other system because if you update now you most likely will have to do some work especially if you are using third party plugins or themes or your own custom created ones. Not to speak of all the security fixes you missed the last five years. Furthermore your install will most likely break once your server will be upgraded to PHP7.
But to your actual problem: Zenphoto does support mp4 and other non image types only via plugins. For mp4 you would need the class-video plugin and some mediaplayer plugin to use them. Zenphoto is file system based so it reads everything that is the /albums folder. So what you need to do is:
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[*]Check if they are really present in your albums within the `/albums` folder
[*]Check if the plugins mentioned are for unknown reasons are disabled and re-enable them. Afterwards they should re-appear again. Naturally they are then considered "new" so you will have to re-order and re-enter titles and descriptions if you had them before (This is also why it is a good idea to have backups of the database).
[*]If that all doesn't help review your server error logs.
[*]Consider to upgrade.
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