The HTC Bolt is a bit of an interesting beast, especially for those into the specs. Considering it has a larger display, compared to the HTC 10, but then it has relatively mid-range specs, and a processor that is going on two years old now in the Snapdragon 810. Perhaps the most puzzling thing here is the fact that the headphone jack has been taken out. Now this isn't unprecedented, considering the Moto Z and Moto Z Force from Lenovo both come without a headphone jack, and of course the iPhone 7 and iPhone 7 Plus also are without one. Both Lenovo and Apple do include adapters in the box, so you can still use your headphones, but for some reason HTC did not. But those that purchased the HTC Bolt are in luck.
One of the freebies that HTC is giving to HTC Bolt users (since it's for the Bolt, that also means it is US only, for now) is a new adapter that gives you a 3.5mm headphone jack, by using the USB-C port on the HTC Bolt. This is definitely something that should have been bundled in the box, but it is great to see HTC providing one for free to everyone that purchased the device. Now you don't need this adapter to use headphones on the Bolt, considering HTC did provide a pair of USB-C headphones with every HTC Bolt, but those that want to use an older pair, that aren't wireless, you'll need this adapter.
All you need to do to get your free adapter is head to the link below. You'll just need to fill out some information about your HTC Bolt purchase, and then you'll be all set. Only HTC Bolt purchases between November 11th, 2016 and January 31st, 2017 will be eligible and you'll have until February 28th, 2017 to submit your request for the adapter. It'll likely take a few weeks before your request is approved and HTC actually sends out the adapter to you, but it's better than nothing. There's no word on whether HTC will be doing something similar for those that buy the HTC 10 evo (the HTC Bolt for international markets).