fix: replace deprecated datetime.utcnow() across the memory subsystem

[kratos0718]

Summary

datetime.utcnow() is deprecated since Python 3.12 and is scheduled for removal in Python 3.14. crewAI's requires-python is >=3.10, <3.14, so users on the currently-supported 3.12 and 3.13 see a DeprecationWarning on every memory write/read, and the project cannot bump its upper bound to include 3.14 without first removing these calls.

This PR replaces all 9 call sites across 4 files in the memory subsystem.

Why the chosen replacement preserves behavior exactly

I used datetime.now(timezone.utc).replace(tzinfo=None) rather than the more modern datetime.now(timezone.utc) because:

1. Persisted data compatibility. MemoryRecord.created_at and last_accessed may already be on disk in users' LanceDB tables as naive datetimes via the existing default_factory=datetime.utcnow. Switching to aware datetimes would either:

   • Break compute_composite_score (naive - aware raises TypeError: can't subtract offset-naive and offset-aware datetimes), or
   • Silently change the on-disk .isoformat() representation from 2026-05-29T05:00:00 to 2026-05-29T05:00:00+00:00, which can affect downstream parsers.

2. Goal of the patch. Remove the deprecation without touching any user-visible semantics.

A follow-up could migrate the whole memory module to timezone-aware datetimes, but that's a separate, behavior-changing PR.

Files changed

File	Call sites	What
memory/types.py	3	2 default_factory on MemoryRecord, 1 in compute_composite_score's recency decay
memory/storage/lancedb_storage.py	4	created_at/last_accessed writes, _parse_dt fallback, batch update timestamp
memory/encoding_flow.py	1	EncodingFlow._apply_actions timestamp
memory/unified_memory.py	1	Memory.update_record timestamp

Each file's from datetime import datetime was extended to from datetime import datetime, timezone.

Verification

• No semantic change: every call still returns a naive UTC datetime, identical to what datetime.utcnow() previously returned.
• No new dependencies.
• No test changes required — existing memory tests continue to pass against this drop-in replacement.

Summary by CodeRabbit

• Refactor
  • Updated internal timestamp handling in the memory module to use standardized UTC datetime generation across all memory operations.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: 96ef7da9-d2fd-44a8-952b-6083e9ac3793

📥 Commits

Reviewing files that changed from the base of the PR and between fca21b1 and 7324392.

📒 Files selected for processing (4)

• lib/crewai/src/crewai/memory/encoding_flow.py
• lib/crewai/src/crewai/memory/storage/lancedb_storage.py
• lib/crewai/src/crewai/memory/types.py
• lib/crewai/src/crewai/memory/unified_memory.py

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📝 Walkthrough

Walkthrough

The pull request replaces all uses of deprecated datetime.utcnow() with datetime.now(timezone.utc).replace(tzinfo=None) across the memory module. Changes span memory type definitions, storage operations, and execution paths, importing timezone from the datetime module to enable timezone-aware UTC timestamp construction.

Changes

Memory Timestamp Standardization

Layer / File(s)	Summary
Memory record types and scoring lib/crewai/src/crewai/memory/types.py	Import timezone and update MemoryRecord.created_at and last_accessed field defaults and compute_composite_score recency calculation to use datetime.now(timezone.utc).replace(tzinfo=None) instead of datetime.utcnow.
Storage implementation timestamps lib/crewai/src/crewai/memory/storage/lancedb_storage.py	Import timezone and update schema placeholder record initialization, _parse_dt fallback parsing, and touch_records methods to generate timestamps using timezone-aware UTC.
Memory operation timestamps lib/crewai/src/crewai/memory/encoding_flow.py, lib/crewai/src/crewai/memory/unified_memory.py	Import timezone and update execute_plans and Memory.update methods to compute last_accessed timestamps using datetime.now(timezone.utc).replace(tzinfo=None).

Estimated Code Review Effort

🎯 2 (Simple) | ⏱️ ~12 minutes

Poem

🐰 Clocks now tick with timezone flair,
UTC aware, beyond compare!
No more .utcnow() in the night,
Each timestamp shines with awareness bright! ✨

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 71.43% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately and concisely describes the main change: replacing deprecated datetime.utcnow() calls across the memory subsystem with the recommended alternative.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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