History synchronization
The body accepts
from_at, to_at, required_before_subscription, and requested_by.
External MT5 movements
POST /api/v1/mam/accounts/{account_login}/balance-transactions/sync-mt5 includes balance movements that did not pass through the API. It accepts lookback_hours or a from_at/to_at interval.
Symbol mappings
MANUAL mappings must be preserved during automatic synchronization. Run first with dry_run=true and review the issue summary.

