From: Butzbach, Germany
No, I don't think so.
As far as I can see the upgrade takes the existing template design and updates all the components with their latest versions, laser 1 to laser 2 etc, this then becomes the template for all new builds. How this is implemented in terms of existing units I am not sure.
Retrofit is a different beast, say I had a Carrier with lasers and fighters and I wanted to change the design to include torpedoes and fighters instead. I retrofit my template to include a switch from lasers to torps. My existing ships will not be affected but will now have an option to be retrofitted into the new design.
Upgraded is an improvement to the components on the existing template.
Retrofits is a change of components on the existing template.
Hope that clears it up.
No, I don´t think so
"Upgrading" generally refers to making a new design for that ship "class".
Assume you have a have a destroyer design "London". You now produce 5 ships of that class, they could be named anything (usually the game calls them London 01, London 02, etc.) you can rename them at will. BUT they will all share the same design "template" London.
Now you decide to make a second destroyer design, take out some engines, add some more lasers. You call it "Manchester".
You decide to take "London 01" and tell it to "retrofit to the latest design". So London 01 will go to a yard and retrofit. It is still called "London 01" afterwards, but it´s design is now a "Manchester".
This is confusing enough as it is. You must take care not to confuse names with designs. Also, you can have several designs of one class "in parallel" - although I don´t recommend it, because it gets confusing even faster.
Now you invent missiles. Several possibilities:
With the AI set to "ai designs ships" in the options, the AI will make new designs for every class of vessel or stations that it thinks should have missiles. It will name them completely new and it won´t care for the subtleties of your previous designs.
So now you have a new destroyer design called "Sheffield", it is the "latest" destroyer design. You will get the pop-up, asking you wether you want to retrofit all your stuff to incorporate the new design. If you click "yes", ALL your destroyers will upgrade to "Sheffield".
UNLESS you marked your "custom", self-made designs to not retrofit automatically. Those will not go and retrofit now. You have to prompt them yourself. This will A) avoid the AI to apply their "run-of-the-mill" designs to all your ships, but B) require you to micromanage upgrading and retrofitting yourself.
The easiest way is to take the "London" design, and hit "upgrade manually". It will open the design screen, add a "MK 2" to your design, obsolete the old design and you can then add the new missiles automatically.
A little more convenient is the "upgrade automatically". It works the same, but will switch out all "old engines" for the "newest engines", for example. Same for shields and reactors. I don´t think it adds new stuff like our missiles, though.
Ideally you can click on the "upgrade" and "retrofit" stances for every design and toggle them from automatically to manual and back. This seems not to work reliably, yet, though.
I have found best results in leaving most of the designs and retrofitting set to automatic, and only have one or two classes really custom-built and maintained. If you want your ships to be specialized in a certain way, just research in that direction (speed, shields, armor, etc.).
Important distinction: Upgrading = changing design blueprints, Retrofitting = actually physically changing your ships in a shipyard.