We have implemented targeted fixes and improvements to enhance cellular data and MMS reliability across various carriers and network configurations. These changes improve communication between the modem, oFono, and the network, with a particular focus on IPv6 compatibility, connection stability, and carrier-specific issues.
MMS improvements
MMS over IPv6
MMS is now supported over IPv6 for both sending and receiving. As carriers continue migrating their networks to IPv6, MMS implementations that only worked over IPv4 were silently failing on IPv6-only and dual-stack configurations. Sending and receiving now work reliably over both protocol families.
Delivery reports
MMS delivery reports are now supported, so the system can confirm when a message has actually been delivered rather than merely handed off. This closes a long-standing feedback gap and makes failures visible instead of silent.
Protocol and routing fixes
- Fixed PDU payload length calculation. Incorrect payload lengths caused some carriers to reject messages outright; lengths are now calculated correctly.
- Non-default MMSC port handling. Carriers that expose their MMSC on a port other than the default no longer break MMS delivery.
- Shared context for MMS and mobile data. MMS can now send over the same context as mobile data, avoiding failed sends when no separate MMS context is available
IPv6 cellular connectivity
- IPv6 cellular connectivity has been improved, including correct IP prefix exposure over DBus. The prefix information surfaced to consumers was previously incomplete or malformed, which broke address configuration and routing for anything that depended on it.
- clatd has been added, providing IPv4 connectivity over IPv6-only cellular networks. Many services and applications still expect IPv4. clatd translates IPv4 traffic over the IPv6-only bearer, so IPv4-dependent software keeps working even on carriers that no longer hand out IPv4 addresses.
5G stability
5G stability is improved via modem technology selection tied to screen state. The modem's radio technology is now selected in line with the screen being on or off, avoiding instability seen when the modem remained in a mode its current power state couldn't sustain. The result is fewer drops and reconnects during everyday use.
oFono reconnection fixes
Reconnection race conditions and crashes in oFono have been resolved. Under rapid connectivity changes such as entering and leaving coverage, toggling airplane mode, or switching radio technologies, oFono could hit race conditions that led to crashes or left it unable to reconnect without a restart. These paths are now handled safely, so cellular data recovery is automatic and dependable.
Together, these changes make cellular connectivity and MMS behave predictably across a much wider range of carrier configurations - IPv4 or IPv6, 5G or LTE - with fewer silent failures and less need for manual intervention.