diff --git a/CHANGELOG.md b/CHANGELOG.md
index 502149e..a12eac2 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,7 +2,7 @@
 
 All notable changes to this project will be documented in this file.
 
-## [4.2.1] - 2026-03-05
+## [4.2.1] - 2026-03-06
 
 ### New Features
 
@@ -10,15 +10,34 @@ All notable changes to this project will be documented in this file.
 - **Identities page**: Import and Export all identities in header (next to New Identity). Per-identity key actions: export key file and copy Base32 shown on hover for the current identity card only. Import modal with upload key file and paste Base32. Backend `GET /api/v1/identities/export-all` returns a ZIP of all identity key files.
 - **Contacts page**: Contacts management UI with routing, localization (en, de, it, ru), and LXMA contact handling. Public key retrieval and tests for LXMA URI handling.
 
+### Security
+
+- **SQL injection hardening**: All raw SQL queries audited and confirmed parameterized. Added `_validate_identifier()` for dynamic table/column names in schema migrations. Legacy migrator `ATTACH DATABASE` path properly escaped; column names from untrusted legacy DBs filtered with regex whitelist.
+
+### Performance
+
+- **Database indexes**: Added 8 new indexes in schema migration 39 covering contacts JOIN columns (`lxmf_address`, `lxst_address`), notification filters (`is_viewed`), map drawings (`identity_hash`), voicemails (`is_read`), archived pages (`created_at`), and a composite index on `lxmf_messages(state, peer_hash)` for the failed-count subquery.
+- **SQLite PRAGMAs at startup**: `journal_mode=WAL`, `synchronous=NORMAL`, `cache_size=8MB`, `mmap_size=64MB`, `temp_store=MEMORY`, `busy_timeout=5s` applied on every database initialization.
+- **Bounded queries**: `search_messages()`, `get_conversations()`, and `get_filtered_announces()` now enforce default LIMIT (500) to prevent unbounded result sets. `get_all_lxmf_messages()` paginated (5000 per page); export endpoint iterates pages.
+- **Slim conversation list queries**: Conversation list queries (`MessageDAO.get_conversations`, `MessageHandler.get_conversations`) now select only the columns needed for the list view, skipping large `content` and `fields` blobs.
+- **Bulk database operations**: Batch methods (`mark_conversations_as_read`, `mark_all_notifications_as_viewed`, `move_conversations_to_folder`) converted from per-row `execute` loops to single `executemany` calls inside transactions. `delete_all_lxmf_messages` wrapped in a transaction for atomicity. Added `DatabaseProvider.executemany()`.
+
 ### Improvements
 
 - **Micron editor**: Button label changed from "Download" to "Save" on the micron editor page (en: Save; de: Speichern; it: Salva; ru: Сохранить).
+- **MicronParser**: Overlay style stripping and improved event handling in NomadNetworkPage.
 - **Release workflow**: Include `meshchatx-frontend.zip` in release assets (was generated and checksummed but not uploaded). Add Linux arm64 build step (AppImage + deb) via `dist:linux-arm64`. Release `files` list now includes `*.zip`.
 - **Community interfaces**: Replaced RNS Testnet Amsterdam and BetweenTheBorders with Quad4 hub (62.151.179.77:45657 TCP). Removed outbound health checks: suggested community interfaces are now a static list with no TCP probes to the internet.
 - **Identities**: Removed top key-control card; key actions moved to per-card hover. Message count and LXMF/LXST addresses on identity list; backend message_count for current identity.
 - **About page**: Security & Integrity section: signed (shield-check) icon and "No integrity violations" badge use green styling in dark mode; status pill has dark-mode emerald variants.
 - **Version management**: Single source of truth is `package.json`; run `pnpm run version:sync` to update `meshchatx/src/version.py`. Build runs sync automatically.
 
+### Testing
+
+- **SQL injection tests**: Unit tests for `_validate_identifier`, integration tests for `_ensure_column` with malicious identifiers, property-based tests for `ATTACH DATABASE` path escaping and identifier regex.
+- **DAO fuzzing**: Hypothesis property-based fuzzing across ContactsDAO, ConfigDAO, MiscDAO, TelephoneDAO, VoicemailDAO, DebugLogsDAO, RingtoneDAO, MapDrawingsDAO, MessageDAO folders, MessageHandler search, `_safe_href`, and utility functions.
+- **Performance regression benchmarks**: Latency (p50/p95/p99) and throughput (ops/sec) benchmarks for announce loading/search, message loading/search/upsert, favourites, and conversation operations. EXPLAIN QUERY PLAN assertions verify index usage. Concurrent read/write contention tests. LIKE search scaling tests across data sizes. Index existence and PRAGMA verification tests.
+
 ## [4.2.0] - 2026-03-05
 
 ### New Features