Source: Wrestling Observer
According to the Wrestling Observer Newsletter TNA and Kurt Angle have agreed to a one year contract extension. According to the report Angle was currently closing in on the final year of a three year deal. The contract apparently had a mutual option for a fourth year and both parties agreed to exercise this option.
The Wrestling Observer has given conflicting reports in the past about contract lengths and renewals so this cannot be confirmed, but many other sources believe this to be the case as well.