How to install a specific update?

[xdeathshot20]

So at my work we are constantly updating phones to newer software.  Mostly iPhones.  The issue is our internet isn't that good so it takes forever to download and install these updates that can be large.  Is there a way to install the update for example iOS 11.3 or what ever the newest software is at the time and just have it there so that when we need to update a phone it just puts it on the phone instead of installing it first then putting it on the phone?

[Radium_Angel]

31 minutes ago, xdeathshot20 said:

So at my work we are constantly updating phones to newer software.  Mostly iPhones.  The issue is our internet isn't that good so it takes forever to download and install these updates that can be large.  Is there a way to install the update for example iOS 11.3 or what ever the newest software is at the time and just have it there so that when we need to update a phone it just puts it on the phone instead of installing it first then putting it on the phone?

If I understand you right, I've done this sort of thing through iTunes. Download the latest patch and copy it to a stored folder so it doesn't have to be re-downloaded again for the next iPhone.