Migration guide from C SDK version 2 or 3 to version 4.

Version 4 of the C SDK is a new design, and therefore NOT backwards compatible with previous versions. The pages below provide instructions on migrating from version 2 or 3 to version 4.

In these pages, v3 refers to both previous versions 2 and 3, which are largely compatible with each other.

Platform layer
Migrating platform from v3 to v4. This must be done before any other component.
MQTT
Migrating an MQTT application from v3 to v4.
Shadow
Migrating a Shadow application from v3 to v4.
Jobs
Migrating a Jobs application from v3 to v4.