I mean if you store your bitcoins in a cold wallet and then we have in the future a fork of bitcoin for some reasons like technology upgrades etc can the forked edition handle this old adresses?
It will have to. If it can't, then nobody will be able to spend any of their bitcoin ever, since there will be no way to spend it out of the old addresses into the new addresses.
This might sound a bit scary if its the first time you've heard it but:
There are no actual bitcoins, and there are no actual addresses at the technical level of how bitcoin operates.
The way the protocol works is that the blockchain stores transactions that list unspent outputs that are to be spent as inputs and new outputs that are to become unspent outputs. The inputs supply a sum of value to the transaction. The new outputs encumber that value with requirements. The most common requirement that an unspent output is encumbered with is a requirement to supply an ECDSA digital signature which must be verifiable with a specific public key. The public key is identified by its RIPEMD-160 hash, which we convert to an "address" to make it easier for humans to work with.
Therefore, anybody that can provide the proper ECDSA signature can "spend" the value associated with the output. If the protocol changes in the future to allow a new way to spend outputs, then new outputs will need to be created that have this new encumbrance. The only way to do that is to first spend the old output by supplying the proper signature. Therefore, nobody will be able to move any of the value to the new encumbrance unless the protocol continues to allow users to spend the existing outputs that have the old encumbrance.
