Chapter 1 · Practice 1 of 3
Move to .NET 10 before .NET 8 and 9 go out of support
Why it matters
.NET ships a new major version every November. Even-numbered releases are LTS with three years of support; odd-numbered releases are STS, which Microsoft now supports for two years.
| Version | Type | Latest patch (Sept 2026) | End of support |
|---|---|---|---|
| .NET 10 | LTS | 10.0.12 | November 14, 2028 |
| .NET 9 | STS | 9.0.20 | November 10, 2026 |
| .NET 8 | LTS | 8.0.31 | November 10, 2026 |
After end of support there are no more security patches. If you are on .NET 8 or 9, the upgrade to .NET 10 is due this month, not next year.
Apply monthly patch releases promptly too: they carry security fixes and do not change APIs. Pin the SDK with a global.json so CI and every developer build with the same version.
Example
{
"sdk": {
"version": "10.0.100",
"rollForward": "latestFeature"
}
}