Particle Device OS Releases

Latest: v6.5.0 (Argon/Boron/B-SoM/B5-SoM/Tracker/Tracker-M/E-SoM-X/M-SoM/P2) · 17 Jul 2026 - Device OS 6.5.0 Release is available in the Web IDE , Particle CLI and Workbench for (Argon/Boron/B-SoM/B5-SoM/Tracker/Tracker-M/E-SoM-X/M-SoM/P2). Released on July 17th, 2026 See documentation about Device OS versions, their current state, upgrades and downgrades here . 6.5.0 FEATURES Multi-byte read() / peek() / write() APIs for hardware UARTs and USB Serial #2935 Per-interface cloud keepalive environment variables ( PARTICLE_CLOUD_KEEP_ALIVE , PARTICLE_CELLULAR_CLOUD_KEEP_ALIVE , PARTICLE_WIFI_CLOUD_KEEP_ALIVE , PARTICLE_ETHERNET_CLOUD_KEEP_ALIVE ) and Particle.getKeepAlive() #2916 Power manager PARTICLE_POWER_INPUT_CURRENT and PARTICLE_POWER_CHARGE_CURRENT environment variables #2928 #2929 ENHANCEMENTS Tethering and cellular (PPP) throughput and reliability improvements (adaptive LCP echo, dedicated PPP TX queue) #2932 [network] SO_LINGER support for faster TCP pcb/pbuf cleanup #2932 [Gen 4] network: improved TCP performance (larger windows/buffers) #2932 [M SoM] M635: Enable 2G fallback support #2933 BUGFIXES [Gen 4] Allow USB CDC ( Serial ) buffers to be resized with acquireSerialBuffer() after first initialization #2932 [Gen 4] usart: fix event handling in interrupt mode UARTs causing reads/writes through waitEvent() (e.g. PPP tethering) to only progress on poll timeouts #2932 [Gen 4] usart: fix RTS/CTS hardware flow control being silently disabled due to slow clock domain register access #2932 [Gen 4] usart: fix FIFO overflow behavior under RTS flow control #2932 [Gen 4] usart: fix DMA-mode USART (NCP or Serial2 on P2/Photon2) available() / peek() not accounting for data still residing in the GDMA FIFO e316605 [Gen 4] usart: fix received data loss when entering sleep with DMA-mode ( Serial2 ) UART e316605 [Gen 4] usart: fix TX buffer handling in interrupt mode e316605 [Gen 3] usart: fix interrupt/normal context race condition causing TX transmissions to never start #2932 [Gen 3] usart: fix multi-byte peek() not seeing all the data reported by available() e316605 [network] tethering: fix TCP MSS clamping in NAT #2932 [Gen 4] [Cellular] muxer: prevent USB starvation and busy looping under heavy cellular traffic #2932 [network] lwip: fix tcp_pcb double-free in tcp_input_delayed_close() #2932 [system] Apply cloud keepalive based on the active network interface when the cloud connection moves between interfaces (ACM) #2916 [Gen 4] usb: fix control interface class driver consuming dataIn / dataOut events for unrelated endpoints #2922 [Gen 4] usb: distinguish between the host halting reads from USB Serial and a slow host #2932 tethering: Fix blocking behavior on writes when tethering over USB #2932 [hal] fix os_thread_join() accessing a stale/freed task TCB #2932 [hal] fix idle hook priority bump when there are threads pending cleanup, keeping terminated thread resources from being freed #2932 [wiring] network: fix null pointer dereference for interfaces without a hardware address #2932 [system] Force cloud connection checks on interface state changes only for interfaces that can carry the cloud connection #2932 Improve I2C driver reliability: Wire.end() in user application no longer breaks PMIC/FuelGauge access in system power manager #2913 Fix race condition on entering POWER_OFF sleep mode with AM18x5 (external RTC) #2927 Fix default cloud keepalive values #2926 [system] Do not run background network connection test if no networks are ready, avoiding LwIP errors when polling with no connected sockets #2930 [Cellular] Workaround for EG916Q returning too large APDU responses #2934 INTERNAL [system] API for scheduling calls in the system thread #2921 iperf3 ( libiperf ) port and tethering throughput HIL test suites (UDP/TCP, bidirectional, USB and Serial1, device-direct cellular paths) #2932 #2920 [hal] Coalesce serial stream implementations into a shared one #2932 [GCC] Multi-byte serial read/write/peek support and poll()-based serial wait events, fix tinker builds #2935 [third_party] lwip : SO_LINGER fixes (abort on close with zero linger timeout, do not abort sockets in LISTEN state), per-pcb RX frame counter for adaptive LCP echo, map ERR_IF to EIO , tcp_pcb double-free fix #2932 [third_party] freertos : expose uxTaskGetNumberOfTasksWaitingTermination() #2932 [third_party] gsm0710muxer : add GSM0710_COOP_YIELD_MS and GSM0710_MAX_TIMEOUT_ITERATIONS to avoid busy looping and time-share CPU #2932 [third_party] coremark : fix builds on the GCC platform #2935 [build] [Gen 3] Reclaim >3KB of flash on LTO-enabled platforms with -flto-partition=one #2928 [test] Flash a dummy OTA at the start of the test runner suite to reset device service maxSameBinaryAttempts counter, which was blocking OTA updates on repeated test runs #2931 [test] Work around spurious USB control transfer stalls (kernel xhci_hcd bug) during pre-sleep mailbox handshake with an explicit mailbox ACK mechanism, propagate mailbox result codes to tests #2923 [test] wiring/sleep20 : make sure pending reset mailbox messages are received by the test runner before the device goes into sleep #2919 [test] wiring/serial_loopback2 : always tri-state the loopback buffer in cleanup #2918 [test] wiring/serial_loopback / serial_loopback2 : parameterize for Serial1 / Serial2 / Serial3 use, cover multi-byte read/write/peek and available() consistency 538a25c System Binaries (all devices) https://github.com/particle-iot/device-os/releases/download/v6.5.0/particle_device-os@6.5.0.zip