I asked this question a few days ago at Workplace.SE community.
The contract stated what I mentioned in the linked question, plus that in twenty years his salary would be around 50-something thousand Euros.
Since the document was optional to sign and required Jim to take online courses outside working hours and pay for them himself, (also having a low salary raise) he decided not to sign it.
A few days after this event, the company notified Jim that he's being terminated, with the reason given that he wasn't planning to stay with the company long-term(20 years).
Can a company give this reason to fire an employee after they decide not to sign an optional contract? Is it legal in Germany?