The patents are still there, but likely no one will give you a problem unless you try to distribute it widely without a license.

I wouldn't be in such a hurry - right now x265 (as far as I know the best HEVC encoder) still loses to x264 in terms of practical use (you only really get better results by using bitrates so low that the end product will look terrible anyway, and x265 loses hard to x264 quality-wise when encoding at similar bitrate and speed). Considering that x264 is backed by about a decade's worth of development, this isn't that surprising.

There are still patent issues, and you still need to obtain a license to use the software. You will never see this image format integrated into any other open source projects, like Firefox, for this reason.

The x265 [1] Project is great. That said, you might want to wait a year for them to improve the encode before messing with your entire collection.

[1] http://x265.org