Our policy is to upgrade customers to newly released versions if they have purchased an older version within 30 days of the new version coming out. We do this automatically in the download center so that you don't need to call in to take advantage of this.
We will continue to come out with new versions of our products; in fact, we are trying to get on a quicker cycle for this. Like a lot of software companies though, it is not our policy to publicize release dates for our product line. While some software companies leak this type of information, release dates are often estimated, or move entirely, and moving a release date can be every bit as unpopular as not offering it in the first place.
As SOJO mentions above, our subscription program is a great alternative if you do not want to pay upgrade costs after the 30-day mark.