b4 Files

[1.48.0] - 2026-05-04

• ADDED: Config backup before update — B4 now automatically saves a copy of your config file before updating (e.g. b4.json.bak.v1.47.2), so you can restore it if needed.
• ADDED: Backup reminder in update dialog — a warning in the update dialog reminds you to download a full backup from Settings → Backup before updating.
• ADDED: Watchdog — background service that monitors configured domains and automatically finds a working bypass when DPI starts blocking them. Add domains or URLs to monitor, and watchdog periodically checks connectivity. After consecutive failures, it runs a quick discovery, applies the first working config, and resumes monitoring. Multiple failed domains are healed together in a single discovery run. Domains with the same working strategy are grouped into one set. Configure intervals, retries, and cooldowns in Settings > Discovery. Live status on the new Watchdog page.
• ADDED: IP block detection — B4 can now detect when a destination IP is blocked entirely (not just by domain name). When detected, B4 immediately resets the connection so your device retries faster on a different server instead of waiting for a timeout.
• ADDED: RST injection protection — B4 can now detect and drop fake TCP RST packets injected by DPI systems to kill your connections. Enable per set in TCP settings. Uses three independent checks: TTL fingerprint mismatch, RST arriving before any server response, and multiple RSTs on the same connection.
• IMPROVED: Fake strategy settings shown only when relevant — Sequence Offset now only appears for Past Sequence and Random Sequence strategies, Timestamp Decrease only for Timestamp strategy. Reduces clutter in the UI.
• FIXED: Error when manual IP overlaps with GeoIP — adding an IP address manually that already exists in a GeoIP category within the same set caused a firewall error. Duplicate IPs are now filtered automatically.
• FIXED: Traffic routing stops working after ~1 hour — GeoIP addresses and static IPs were added to firewall sets with a TTL and silently expired. They are now permanent. DNS-resolved IPs are periodically refreshed before they expire.

What's Changed

• feat: implement IP block detection and improve UI settings for TCP co… by @DanielLavrushin in https://github.com/DanielLavrushin/b4/pull/172
• chore: remove swagger documentation update job from release workflow by @DanielLavrushin in https://github.com/DanielLavrushin/b4/pull/174
• feat: add watchdog functionality for domain monitoring by @DanielLavrushin in https://github.com/DanielLavrushin/b4/pull/175
• feat: implement periodic re-resolution for routing and enhance IP han… by @DanielLavrushin in https://github.com/DanielLavrushin/b4/pull/176
• feat: add TCP RST protection configuration and handling by @DanielLavrushin in https://github.com/DanielLavrushin/b4/pull/177
• Refactor code structure for improved readability and maintainability by @DanielLavrushin in https://github.com/DanielLavrushin/b4/pull/178
• Refactor code structure for improved readability and maintainability by @DanielLavrushin in https://github.com/DanielLavrushin/b4/pull/179
• Add config backup feature and update dialog warning by @DanielLavrushin in https://github.com/DanielLavrushin/b4/pull/180

Full Changelog: https://github.com/DanielLavrushin/b4/compare/v1.47.2...v1.48.0