Philips has recently announced (via Engadget) that they will be dropping third-party bulb support. Prior to this, users could use third-party bulbs but apparently due to numerous issues that kept cropping up, Philips decided that it was better to just drop the support to prevent any misconceptions or confusion about its products.
According to Philips, “Next to confusing differences in setup and resetting, we’ve encountered a number of such issues over the years including 3rd party lights which do not turn off when we fade them to off, lights which do not react correctly to scene recalls and lights which stop proper functioning of our Wireless Dimmer Kits.”
The good news is that third-party support will come back in the form of the Friends of Hue program. This is basically like a certified program where Philips will sign off on third-party products that they believe will work consistently. So if you are using a third-party bulbs this is something to take into consideration.