Allow me to expand on my comment.
Your answer is not correct because you say:
When they broke the contract by not notifiying you, that gave you the right to either walk away from the contract or try to amend it with them.
Generally, if one side won't hold it's end of a contract it is broken. You can read more about the legal principle here: https://www.upcounsel.com/anticipatory-breach
This is, as a whole, plainly wrong for the following reasons:
- "they broke the contract by not notifiying you" assumes facts not in evidence but in the context of the site we can let this slide.
"that gave you the right to ... walk away from the contract" - no, no, no, a thousand times no! Failure to notify the OP of the upgrade is only a warranty of the contract Breach of contract by one party allows the innocent party to:
- repudiate the contract and sue for damages for a breach of a condition of the contract
- repudiate the contract and sue for damages for a breach of an intermediate term of the contract if the breach is serious
- sue for damages for a breach of an intermediate term of the contract if the breach is minor
- sue for damages for a breach of a warranty of the contract
"Generally, if one side won't hold it's end of a contract it is broken", no - see above. Only in very specific circumstances does a breach by one side allow the other side to terminate the contract. "Generally" a contract remains binding.
- The link to anticipatory breach is not relevant - there has been an actual breach by the OP's client. The only anticipatory breach would be if the OP indicated that he would not fulfill his obligations. Your advice to the OP is extremely likely to make the OP liable for damages.
So, the answer is not only wrong, its dangerous.
The other answer is not like yours as it does not assert (wrongly) that the contract is at an end.
Legal termination of a contract other than by performance or agreement is extremely technical and hard to get right. It is extremely dangerous to walk away from a contract even when the other party is obviously in breach of it - most breaches allow you to sue only, they do not allow you to terminate.
I believe that my comment (and vote) were perfectly valid.