impOS 34 Beta available

We’re happy to announce the imminent availability of impOS 34 to beta developers.


The major changes in this release are:

  • We have added official support for the new imp005 module, which provides USB, Ethernet and 2.4/5GHz WiFi bands, as well as lots more RAM, a faster CPU and double the code space offered by the imp001 and imp002.

  • The memory available for Squirrel bytecode in the imp003 has doubled to 256KB.

  • Additional network configuration options, including static IP address and connection via a proxy server, are available for all imps.

  • Extensions to UART configuration to permit more precise timing control, allowing better integration with RS485 and serial protocols such as Modbus RTU.

  • We have moved from using eCos as our embedded RTOS to impose (imp Operating System Environment). This has been designed to be power and space efficient, and allows us to more easily target new hardware.

  • We have upgraded our connection security from TLS1.0_RSA_WITH_AES_128_CBC_SHA to TLS1.2_ECDHE_RSA_WITH_AES_128_CBC_SHA256, and increased our RSA key length from 1024 bits with a 2048 bit CA to 2048 bits with a 4096 bit CA. ECDHE gives “forward secrecy” on every imp connection, meaning that even if device or server certificates are obtained, connection traffic is still secure as a per-session ephemeral DH key is used to secure traffic.

  • Our upgrade format has been improved, and all upgrades are now signed by RSA4096 bit keys held within a FIPS140-2 Hardware Security Module (HSM), which provides greatly increased protection of our root of trust.

  • Device authenticity is further confirmed using an ed25519 challenge-response as part of the connection process. This uses the per-device secrets that are provisioned into every imp at time of manufacture.

For more features, and more detail on the above, see our release notes.

You can find documentation for the new features in our Dev Center.

Upgrade process

If you would like to receive this beta update, please email, with your account name and the MAC addresses of DEVELOPER DEVICES ONLY that you’d like to have upgraded.

If you are not already a beta developer, you will be added to our beta group.

Please note that you’ll automatically receive any further 34.x releases that pass our internal testing, up to and including the final GA release.


Obviously, we’d be very glad to hear your feedback, good or bad. Please post your feedback as replies to this post, or email

Note: It will help us resolve any issues faster if you provide replication steps, and describe exactly how the actual behaviour differed from your expectations.

We appreciate your support!

The Electric Imp team