The first is the ability to create hidden encrypted operating systems when using whole-disk encryption. This works in a similar fashion to hidden encrypted disk containers. That is, you have a primary boot partition that is encrypted with one password, and a second virtual one that is contained within the primary, but encrypted with another password. The password you enter will determine which partition is loaded and, without knowing the password, it is impossible to know that there is a second hidden operating system. This is called plausible deniability and allows you to have a “decoy” or “safe” operating system to open if, for example, you were under duress. While most of us aren’t spies, this feature may still come in handy.
The other new features are more performance and reliability enhancements. TrueCrypt is now multi-core aware, so if you’re creating a lot of encrypted disks, the time to encrypt them will now be halved on a dual-core, quartered on a quad-core, etc. In the area of reliability, the team have added header redundancy so you have a greater chance of recovering a damaged container or partition.
For regular use, you probably won’t notice a lot of difference, but none-the-less, it’s another great release from the TrueCrypt team.