Azure Functions 3.0 is the next major version of the Azure Functions host and service running on .NET Core 3.0. This will be a highly backwards compatible release, with the major version change driven by runtime updates and new major versions of core dependencies.
The backwards compatibility goal brings the following benefits:

• Extensions built for 2.0 will be compatible with Azure Functions 3.0
  • Extension authors will not need to make any changes to their extensions
  • Extensions will not need to be reinstalled when migrating from 2.0 to 3.0
  • The same extension versions will work against 2.0 and 3.0
    NOTE: This applies to the extension API surface and extensions targeting .NET Standard only. If the extension targets something other than .NET Standard, they may be impacted by the version change.
• The majority of customers should be able to migrate from 2.0 to 3.0 with no code changes. Changing the runtime version should be all that is needed to move to the new version.
• Language workers (JavaScript, Python, Java, PowerShell) will continue to work with the new version of the runtime (no changes to the out-of-proc layers protocol)

We’ll continue to update this issue with information about gaps, potential breaking changes and known issues as releases become available.

Timelines

A public preview will be available in October 2019
General Availability, running on .NET Core 3.1 (LTS release), scheduled for Q1 2020

Are you deprecating Azure Functions 1.0 or Azure Functions 2.0?

No. This is not a deprecation announcement and the Azure Functions 3.0 preview or GA releases have no impact on the planned support for Azure Functions 1.0 or Azure Functions 2.0.

For questions and comments, please use: Azure/app-service-announcements-discussions#115