I have started my experiments with Philips Hue with white bulbs, and so far it looks appealing. I would like to go on and add some more interesting bulbs, namely Osram Lightify Tunable White. Googling hasn't helped yet: Do I need to buy an Osram Bridge too, or can I pair an Osram bulb directly to the Philips Hue bridge?
Old outdated information about EU vs US firmware. https://www.reddit.com/r/Hue/comments/42840b/howto_make_american_osram_lightify_bulbs/
The firmware is now combined into one compatible version. Try this, several people report they work: https://recoveringappleholic.wordpress.com/2016/01/23/how-to-get-lightify-to-work-with-hue/
I believe @DanielGriscom was talking out of turn and sharing his thoughts that were based off poor assumptions rather than research.