If any company or organisation suddenly folds and posts a warrant canary, it should be considered compromised.
As a non-maintained application eventual bugs will not be corrected, this is the reason of the warning. It seems than the project was dumped because of code licence issue between one of the developer and its ex-company accusing him of having stolen the code. So the developers just drop the project: Who will bother taking legal risk for a free project?
You can still download truecrypt from truecrypt.ch a site from two of the original developers' group.