Elect new IC/GuestOS revision (commit fffab35)

Release Notes for release-2026-08-06_04-21-base (fffab354a5cf76bf40ea3e0742de29e293277ff3) This release is based on changes since release-2026-07-31_04-23-base (e3d101b22ae3fa02aca737f9fb96cc6c4ca83ac3).

Please note that some commits may be excluded from this release if they're not relevant, or not modifying the GuestOS image. Additionally, descriptions of some changes might have been slightly modified to fit the release notes format.

To see a full list of commits added since last release, compare the revisions on GitHub.

Features:

• ea38c7df0 Core Protocol: introduce SystemMetadata::subnet_merged (#11025)
• 525a442f2 Core Protocol: allow composite queries to call the management canister query methods (#10987)
• 956b33ee8 Core Protocol: Increase maximum number of canisters to 250k (#11036)
• 18e226db2 Core Protocol: Make snapshots immutable after loading (#11029)
• b3a371e80 Core Protocol: migrate non-governance canisters to new ic_cdk call interface (#10995)
• 54259de9a Core Protocol: inline env-file-reader (#11011)
• abd3faccb Core Protocol: Consensus cost of non-flexible HTTP outcalls must be covered by allowance (#10967)
• 0daf77e26 Core Protocol: bump opentelemetry (#11005)
• e01e2d332 Core Protocol: Make query limits configurable in the SubnetRecord (#10882)
• 198de6d85 Core Protocol(subnet-splitting): implement subnet splitting's halting logic (#10936)
• 9899fcbf1 Core Protocol: Credit delivered HTTP refunds to canisters and report cycles metric (#10727)
• 2e425e15d Node: Create variants that can deploy multiple copies of GuestOS to a single node (#10457)

Bugfixes:

• 1855fcdbe Core Protocol: debug_assert against recording IngressStatus::Unknown (#11015)
• 7cc19175d Core Protocol: cycles accounting for mgmt canister operations (#10859)
• 17eb31557 Core Protocol: make ingress history writes more eager (#11000)
• 43d0b1fa8 Core Protocol(core): Limit signing key lengths (#10925)

Chores:

• 743a93350 Core Protocol: Bump current certification version to V28 (#11033)
• 9e2920593 Core Protocol(bazel): replace hermetic_cc_toolchain (zig cc) with hermetic-llvm (#10991)
• 462b68ca3 Core Protocol: drop deleted canisters from RoundSchedule (#11004)
• 03b28a275 Core Protocol: Upgrade wasmtime to v47 (#10994)
• 76555c996 Core Protocol: migrate to ic-cdk's new print, spawn and reply (#10971)
• 42413a1c7 Node: Update Base Image Refs [2026-07-30-0854] (#10961)

Refactoring:

• 3238722b2 Core Protocol: Restrict which CompoundCycles specializations can be consumed directly (#11021)
• dd7cb274f Core Protocol(state_manager): stop checking the legacy canister log index on checkpoint load (#11013)

Tests:

• 3cf82a06a Core Protocol: exercise every ingress state in the test_backward_compatibility fixture (#11028)

Documentation:

Full list of changes (including the ones that are not relevant to GuestOS) can be found on GitHub.

IC-OS Verification

To build and verify the IC-OS GuestOS disk image, after installing curl if necessary (sudo apt install curl), run:

# From https://github.com/dfinity/ic#verifying-releases
curl -fsSL https://raw.githubusercontent.com/dfinity/ic/fffab354a5cf76bf40ea3e0742de29e293277ff3/ci/scripts/repro-check | python3 - -c fffab354a5cf76bf40ea3e0742de29e293277ff3 --guestos

The two SHA256 sums printed above from a) the downloaded CDN image and b) the locally built image, must be identical, and must match the SHA256 from the payload of the NNS proposal.

While not required for this NNS proposal, as we are only electing a new GuestOS version here, you have the option to verify the build reproducibility of the HostOS by passing --hostos to the script above instead of --guestos, or the SetupOS by passing --setupos.