Hello, I have an Apple Watch Generation 3 that needs software. I went to the maintenance technician and he told me that this version has been discontinued since the 12th. Sorry, when will this version be back to work, thank you

For Apple Watch to pair with an iPhone you need

• To use your Apple Watch Series 3 or later with watchOS 8, you need to pair your Apple Watch with an iPhone 6s or later with iOS 15 or later. Setup assistants on your iPhone and Apple Watch work together to help you pair and set up your Apple Watch.
• To use your Apple Watch Series 3 or later with watchOS 7, you need to pair your Apple Watch with an iPhone 6s or later with iOS 14 or later. Setup assistants on your iPhone and Apple Watch work together to help you pair and set up your Apple Watch.
• To use your Apple Watch Series 1 or later with watchOS 6.2, you need to pair your Apple Watch with an iPhone 6s or later with iOS 13 or later. Setup assistants on your iPhone and Apple Watch work together to help you pair and set up your Apple Watch.
• To use your Apple Watch Series 1 or later with watchOS 5, you need to pair it with an iPhone 5s or later with iOS 12 or later—Apple Watch models with cellular require an iPhone 6 or later. Setup assistants on your iPhone and Apple Watch work together to help you pair and set up your Apple Watch.

Apple Watch models supporting watchOS 7 can also support watchOS 8. However, like watchOS 7, watchOS 8 has limited support on Apple Watch Series 3.

The latest version of WatchOS for a series 3 is 8.4.2. I updated mine to this just a couple of days ago.