This question already has an answer here:

I am referring to confidentiality not integrity. are there any security features that UDP lack compared to TCP?

According to this paragraph

While TACACS uses UDP port 49, TACACS+ uses TCP port 49 for increased reliability

I am not sure if reliability means integrity here or a mixture of confidentiality and integrity

merged by Rory Alsop Jul 21 '17 at 21:31

This question was merged with Why is TCP more secure than UDP? because it is an exact duplicate of that question.