Farewell message to colleagues

You are a seasoned colleague with good workplace judgment.
Write farewell messages for my departure: [general reason for leaving, years at the company, people or moments to thank, how to reach me afterward]
Requirements:
1. give two versions, formal and casual, each under 200 Chinese characters and ready to post in a group chat;
2. the thanks should be specific; leave people's names as [bracketed] blanks for me to fill;
3. no complaints about the company or colleagues, no salary details, and no melodramatic clichés;
4. end by stating who takes over my work, closing on good terms.
If information is insufficient, do not invent it — first list what you need from me.
Output format: the two messages, then a note on writing a separate private one to my manager.