* Backend/S3: The default of `use_legacy_workflow` changed to `false` and is now deprecated. The S3 backend will follow the same behavior as AWS CLI and SDKs for credential search, preferring backend configuration over environment variables. To support the legacy credential search workflow, you can set this option as `true`. It'll be completely removed in a future minor version.
* Add support for a `removed` block that allows users to remove resources or modules from the state without destroying them. ([#1158](https://github.com/opentofu/opentofu/pull/1158))
* Provider-defined functions are now available. They may be referenced via `provider::<provider_name>::<funcname>(args)`. ([#1439](https://github.com/opentofu/opentofu/pull/1439))
* Added `templatestring` function that takes a string and renders it as a template using a supplied set of template variables. ([#1223](https://github.com/opentofu/opentofu/pull/1223))
* Added `base64gunzip` function that takes a base64 encoded gzip string and returns the decompressed data as a string. ([#800](https://github.com/opentofu/opentofu/issues/800))
* Added `cidrcontains` function that determines if an address belongs to a certain prefix. ([#366](https://github.com/opentofu/opentofu/issues/366))
* Added `urldecode` function that will decode a url-encoded string. ([#1234](https://github.com/opentofu/opentofu/issues/1234))
* Previously, every call to state.Write() would also Persist to disk. This was not following the intended API and had longstanding TODOs in the code.
* This change fixes the local state filesystem interface to function as the statemgr API describes.
* A possible side effect is that a hard crash mid-apply will no longer have a in-progress state file to reference. This matches the other state managers.
* Allow referencing the output from a test run in the local variables block of another run (tofu test). ([#1254](https://github.com/opentofu/opentofu/pull/1254))
*`import` blocks `to` address can now support dynamic values (like variables, locals, conditions, and references to resources or data blocks) in index keys. ([#1270](https://github.com/opentofu/opentofu/pull/1270))
* Fix view hooks unit test flakiness by deterministically waiting for heartbeats to execute ([$1153](https://github.com/opentofu/opentofu/issues/1153))
*`tofu test` resources cleanup at the end of tests changed to use simple reverse run block order. ([#1043](https://github.com/opentofu/opentofu/pull/1043))
* Fix `tofu show` and `tofu state show` not working with state files referencing Terraform registry providers in some instances ([#1141](https://github.com/opentofu/opentofu/pull/1141))
* S3 backend no longer requires to have permissions to use the default `env:` workspace prefix ([#1445](https://github.com/opentofu/opentofu/pull/1445))
* Fixed a crash when using a conditional with Twingate resource ([#1446](https://github.com/opentofu/opentofu/pull/1446))
* Added support for user-defined headers when configuring the HTTP backend ([#1427](https://github.com/opentofu/opentofu/pull/1487))