Support reply (MFonk, 7/22/2026) confirms both open questions: all calls (incoming and outgoing) are blocked in real time at $0 balance, not just via the recurring-fee grace-period mechanism, and the 4 signaling IPs already hardcoded into this doc's research notes are still current. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01Ho9mZgAkVpdz7S5wJkg8Nf