I am facing a difficult situation at work.

I started at my current company four years ago asa a junior developer. Today I am an unofficial manager, delegating work and possessing the most technical knowledge in my team. I got additional responsibilities thanks to hard work and countless hours studying and educating myself. However, three years of negotiations only got me the official title of Software Engineer.

I recently realised that my manager has no interest in my career development.
I wanted to be transferred to another team, and his initial declining escalated into a conversation that involved senior management and the CIO.

The other team collaborated with me in the past and would be happy to have me. However, escalating tensions with my current manager led to a fallout which ultimately involved HR.

My manager ultimately was pressured into agreeing to the transfer, but we still 
have work together for two months. He is now spreading rumours about me.

I don't want anyone to mischaracterise my behaviour or decisions. I have email proof that my manager is spreading rumours and the last thing I want to do is get him fired. However, I do not want to be bullied in the next two months.

My question is: **how could I tell my boss he can't bully me without causing conflicts that can prevent me from reaching my work objectives?**