Release Notes for [release-2026-07-31_04-23-base](https://github.com/dfinity/ic/tree/release-2026-07-31_04-23-base) (`e3d101b22ae3fa02aca737f9fb96cc6c4ca83ac3`)
This release is based on changes since [release-2026-07-23_04-21-base](https://dashboard.internetcomputer.org/release/1153c70d98a51ec2f023be9b3ce1d50c6b67da21) (`1153c70d98a51ec2f023be9b3ce1d50c6b67da21`).

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](https://github.com/dfinity/ic/compare/release-2026-07-23_04-21-base...release-2026-07-31_04-23-base).
## Features:
* [`e3d101b22`](https://github.com/dfinity/ic/commit/e3d101b22) Core Protocol(Core): Switch to deterministic memory tracker ([#10789](https://github.com/dfinity/ic/pull/10789))
* [`e73589fd6`](https://github.com/dfinity/ic/commit/e73589fd6) Core Protocol(subnet-splitting): add subnet splitting status field to summary ([#10933](https://github.com/dfinity/ic/pull/10933))
* [`a9372bcba`](https://github.com/dfinity/ic/commit/a9372bcba) Core Protocol: Export renamed consumed-cycles metrics under new names ([#10892](https://github.com/dfinity/ic/pull/10892))
* [`0f3c60f6a`](https://github.com/dfinity/ic/commit/0f3c60f6a) Core Protocol: enable replicated fetch_canister_logs ([#10879](https://github.com/dfinity/ic/pull/10879))
* [`91c7a2cb1`](https://github.com/dfinity/ic/commit/91c7a2cb1) Core Protocol: Deliver initial spent HTTPS outcalls cycles ([#10897](https://github.com/dfinity/ic/pull/10897))
* [`7d259f65c`](https://github.com/dfinity/ic/commit/7d259f65c) Core Protocol: introduce `BackwardsCompatible` ([#10694](https://github.com/dfinity/ic/pull/10694))
* [`8a5b407c3`](https://github.com/dfinity/ic/commit/8a5b407c3) Node: Update config, regardless of NO keys ([#10800](https://github.com/dfinity/ic/pull/10800))
## Bugfixes:
* [`4efca3fd6`](https://github.com/dfinity/ic/commit/4efca3fd6) Core Protocol: cycles metrics in the certified state tree ([#10843](https://github.com/dfinity/ic/pull/10843))
* [`f0cc13d4b`](https://github.com/dfinity/ic/commit/f0cc13d4b) Core Protocol: account for canister history memory usage ([#10825](https://github.com/dfinity/ic/pull/10825))
* [`b12ce42b9`](https://github.com/dfinity/ic/commit/b12ce42b9) Core Protocol: deflake //rs/execution_environment:memory_matrix_test ([#10932](https://github.com/dfinity/ic/pull/10932))
* [`af4619d68`](https://github.com/dfinity/ic/commit/af4619d68) Core Protocol: resolve uninstall_code effective canister id with UninstallCodeArgs ([#10934](https://github.com/dfinity/ic/pull/10934))
* [`0d79c5d09`](https://github.com/dfinity/ic/commit/0d79c5d09) Core Protocol: Use regular cost for Wasm64 compilation ([#10918](https://github.com/dfinity/ic/pull/10918))
* [`90f14675a`](https://github.com/dfinity/ic/commit/90f14675a) Core Protocol: account for fetch_canister_logs instructions ([#10687](https://github.com/dfinity/ic/pull/10687))
* [`bec4d3885`](https://github.com/dfinity/ic/commit/bec4d3885) Core Protocol(nns_delegation_manager): use custom DNS resolver in tests ([#10862](https://github.com/dfinity/ic/pull/10862))
## Performance improvements:
## Chores:
* [`483a94d5b`](https://github.com/dfinity/ic/commit/483a94d5b) Core Protocol: Log created or received IDKG complaints ([#10951](https://github.com/dfinity/ic/pull/10951))
* [`a1d61d448`](https://github.com/dfinity/ic/commit/a1d61d448) Core Protocol: Increase current certification version to V27 ([#10944](https://github.com/dfinity/ic/pull/10944))
* [`3622b58e7`](https://github.com/dfinity/ic/commit/3622b58e7) Core Protocol(bazel): bump rules_rust to bazelbuild/rules_rust@5f04c8c1 ([#10900](https://github.com/dfinity/ic/pull/10900))
* [`c8da0a12c`](https://github.com/dfinity/ic/commit/c8da0a12c) Core Protocol(core): Bump libflate ([#10911](https://github.com/dfinity/ic/pull/10911))
* [`da1ef8073`](https://github.com/dfinity/ic/commit/da1ef8073) Core Protocol: Make HTTP context's cost schedule mandatory and start using it ([#10872](https://github.com/dfinity/ic/pull/10872))
* [`0d0c9a0e9`](https://github.com/dfinity/ic/commit/0d0c9a0e9) Core Protocol: bump nix 0.24.3 -> 0.31.3 ([#10880](https://github.com/dfinity/ic/pull/10880))
* [`fba107bca`](https://github.com/dfinity/ic/commit/fba107bca) Core Protocol,Node: use new ic-cdk apis ([#10920](https://github.com/dfinity/ic/pull/10920))
* [`dd4c052d8`](https://github.com/dfinity/ic/commit/dd4c052d8) Core Protocol,Node: use new ic-cdk naming ([#10886](https://github.com/dfinity/ic/pull/10886))
* [`5dbfe6624`](https://github.com/dfinity/ic/commit/5dbfe6624) Node: evaluate Remote Build Execution (RBE) @ Namespace ([#10579](https://github.com/dfinity/ic/pull/10579))
* [`e8e9c7a77`](https://github.com/dfinity/ic/commit/e8e9c7a77) Node: Update Base Image Refs [2026-07-28-0145] ([#10922](https://github.com/dfinity/ic/pull/10922))
* [`e0c0a5fc6`](https://github.com/dfinity/ic/commit/e0c0a5fc6) Node: Bump boundary node crates ([#10917](https://github.com/dfinity/ic/pull/10917))
* [`b9425e835`](https://github.com/dfinity/ic/commit/b9425e835) Node: Update Base Image Refs [2026-07-24-0145] ([#10891](https://github.com/dfinity/ic/pull/10891))
* [`394334358`](https://github.com/dfinity/ic/commit/394334358) Node: Update Base Image Refs [2026-07-23-0851] ([#10874](https://github.com/dfinity/ic/pull/10874))
## Refactoring:
## Tests:
## Documentation:
## Other changes:
Full list of changes (including the ones that are not relevant to GuestOS) can be found on [GitHub](https://github.com/dfinity/dre/blob/63584c19f1c7e66700bcec47c9f48887e7eec029/replica-releases/e3d101b22ae3fa02aca737f9fb96cc6c4ca83ac3.md).

# 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/e3d101b22ae3fa02aca737f9fb96cc6c4ca83ac3/ci/scripts/repro-check | python3 - -c e3d101b22ae3fa02aca737f9fb96cc6c4ca83ac3 --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`.
