Haystack releases version 3.4.0 with Python 3.15 support

Haystack has released version 3.4.0, which introduces official support for Python 3.15. Following this update, Python 3.10 is no longer supported, as the minimum required version is now Python 3.11 due to Python 3.10 reaching its end of life in October 2026.

The update includes an experimental feature called ToolResultOffloadCompactor. This new compaction strategy for CompactionHook allows agents to compact context without losing tool results by writing them to a ToolResultStore and leaving a reference. This enables agents to read full outputs back on demand via a specific read tool.

Additionally, the release standardizes the page_number metadata field across all splitters, ensuring consistency in how page numbers are reported.