Add support for auth date-based versioned API

[valdave]

Due to requirements of this migration https://developers.hubspot.com/docs/api-reference/legacy/authentication/oauth-tokens/v1/migration-guide need a posibility to use this methods for auth.

[lucabartoli]

They have been marking every API in this SDK as “legacy” for months across all public documentation, yet there is still no official replacement SDK available.

We’re approaching the 2026-09 release, and we still don’t have support for the 2026-03 APIs.

Sadly, we’ve been putting up with this SDK mess for years because it was auto-generated and supposedly easier for them to maintain. And yet we still have:

• Broken PHP documentation
• Lack of updates
• Missing APIs
• Incorrect responses for some endpoints

More broadly, this seems to reflect HubSpot’s overall approach lately: ship and don’t look back.

Just to mention a few issues we’ve dealt with in the last month alone:

• Broken APIs (for example, the custom workflow actions PATCH endpoint took two weeks to be fixed)
• Broken CLI tools (the platform migration process crashed with cryptic errors, with no way to proceed or roll back; we ended up rebuilding the app from scratch)
• Deprecations without a clear migration plan (if you’re going to deprecate something, provide a sunset date and a migration path; otherwise it’s just an excuse not to maintain backward compatibility when new features break existing functionality)

At this point, it feels like developers are no longer a priority, and that most efforts have been redirected toward strategic partnerships and AI initiatives.

Hopefully, they will eventually migrate all APIs to the new platform. My guess is that they’re still trying to figure out how to handle API prefixes changing every six months, while supporting multiple API lifecycles and maintaining SDK versioning at the same time.