Hi, seems lots of people are confused about the iPhone model variations, learning a lot from the previous gens (5S), I am putting together this guide here with reference from previous shares on the forum, hope it helps: AT&T A1549 / A1522 GSM -- These two models will also be sold in many other countries that do not have TD LTE however LOCK / Unlock status will depend on that specific carrier / network. Unlocked: If purchased from Apple store full retail price device only Locked: If purchased from Apple at the subsidized price, AT&T, or any other 3rd party retailer (2yr Contract / Next Plan) Note: Can easily be unlocked for Cheap using remote IMEI sites (does not matter whether phone is in contract or not) Carrier: AT&T will unlock your iPhone 6 / 6 Plus once your contract is completed per request. Unlock works for any GSM carrier, US or other countries Will it work?: Yes This model will work on AT&T / T-Mobile and all MVNO networks that use AT&T / T-Mobile towers + All other GSM networks worldwide. Verizon A1549 / A1522 CDMA Unlocked: No matter where purchased or at what price, ALL Verizon iPhone 6 / 6 Plus are unlocked right out of the box. Even if they are bought from Verizon or 3rd party retailers at the subsidized price. Can never be carrier locked. The is due to an FCC requirement for Verizon LTE phones. Will it work?: Yes This model will work on Verizon / AT&T / T-Mobile and all MVNO networks that use AT&T / T-Mobile towers + All other GSM networks worldwide. T-Mobile A1549 / A1522 GSM Unlocked: If purchased from Apple Store at Full Price It will be unlocked -- EIP / contract pricing not available via Apple Store / Apple.com Locked: If purchased from a T-Mobile retail store whether financing or at full retail price or via 3rd party store on T-Mobile contract/financing plan. Phone will be LOCKED. Carrier: T-Mobile allows you to request an unlock for your phone after 40 days of service with the carrier. Unlock works for any GSM carrier. US and other countries. Will it work?: Yes This model will work on AT&T / T-Mobile and all MVNO networks that use AT&T / T-Mobile towers + All other GSM networks worldwide. Sprint / US Cellular / C-Spire A1586 / A1524 These two models will also be sold in many other countries that do have TD LTE however LOCK / Unlock status will depend on that specific carrier / network. Unlocked: This phone can ONLY be unlocked by at the discretion of Sprint / US Cellular / C-Spire. After 90 days of service and paying your bill on time Sprint will allow you to request an unlock of your iPhone. Locked: This phone will be locked no matter where or how you purchased it. Full retail or subsidized. Note: Even when Sprint / US Cellular / C-Spire 'unlocks' your iPhone, it is only for international use. It CANNOT be used on domestic GSM carriers like AT&T or T-Mobile. This means that in the USA your phone can only be used on Sprint / US Cellular / C-Spire even if it is unlocked. No exceptions. Will it work?: No because Sprint / US Cellular / C-Spire Unlock Policy does not allow you to use the iPhone on any GSM network within USA -- Unlocking is virtually impossible by Sprint / US Cellular / C-Spire. Please Understand: iPhones are designed to be universal, All variations of iPhones contain official Carrier Settings for All Global carriers/networks that officially sell the iPhone as part of their phone lineup. Hence MMS+Visual Voicemail (If supported by network) will work by simply inserting that Carrier/Network's SIM into the iPhone. If you are using the iPhone on a "Unsupported" network AKA network that does not currently sell the iPhone as part of its phone lineup, then you will be able to enter the APN / MMS settings via Cellular Data Network option available under "Carrier". So Example: if you buy a Verizon iPhone 5S / 6 / 6Plus and want to use it on AT&T or T-Mobile, all you need to do is insert the SIM and EVERYTHING will work out of the box literally. This is the simplify that the iOS / iPhones are designed with in mind. You can Find the iPhone Model and see if your country LTE is supported here: http://www.apple.com/iphone/LTE/ <--- Please note there is error on Apple Site, First Batch should say A1549 and A1522 GSM and CDMA respectively -- and if you don't see your iPhone 6 / 6 Plus listed with your country, look at iPhone 5S -- All iPhone 5S LTE bands are supported on iPhone 6 / 6 Plus -- Just a matter of Apple updating the full list (Hopefully they will do soon) Recommend Model to buy at Full Price: 1st Choice: Verizon iPhone 6 (A1549 CDMA) or iPhone 6 Plus (A1522 CDMA) -- Give you most flexibility & freedom to use Verizon, AT&T, T-Mobile with Full 3G/4G + LTE and all other MVNO's + Global networks. 2nd Choice: GSM iPhone 6 (A1549 GSM) or iPhone 6 Plus (A1522 GSM) Either AT&T or T-Mobile and have them unlock it or get it unlocked from 3rd party -- Give you freedom to use AT&T, T-Mobile with Full 3G/4G + LTE and all other MVNO's + Global networks. I'm hoping this helps, if you have any seriously technical questions you can BBM to: 79F758CA for more info.