Many of the adventures published during the previous editions of D & D are still useful for the DM of the fifth edition, mainly because the general base of monsters and treasures in all editions is quite similar, while the main aspect of the adventures, the plot , is usually related to the Rules of its original edition.
I am, at this moment, DMing some modules D & D 4E for my group, the trilogy H1-H2-H3: Follow in the Shadowfell, Thunderspire LabyrinthY Pyramid of shadows. The adaptations that I normally have to make are to balance the matches and choose the rewards of the players. I am following the guidelines of the Dungeon Master's Guide Y The Xanathar guide for everything and I have not encountered any problem in terms of converting these adventures.
Wizards of the Coast has an official conversion document that can help you convert older modules, according to the rules.
One important thing to keep in mind is that White feather mountain It has already officially become 5E. It was published in Tales from the yawn portal, a book that presents a number of adventures from previous editions adapted to be executed in D & D 5E, including The citadel without sun, The forge of fury, Against the giants And some others
The next Ghosts of Saltmarsh, which will be launched in May, will also include conversions of some modules from previous editions, this time, adventures based on the sea / pirates.