> ## Documentation Index
> Fetch the complete documentation index at: https://prod-mint.classiq.io/llms.txt
> Use this file to discover all available pages before exploring further.

# 1.9.0

Released on 2026-04-19.

## Upgrade Instructions

* [Python SDK](../getting-started/registration_installations.md/#platform-version-updates)
* The IDE upgrades automatically.

## Enhancements

* **`ExecutionSession.sample` and `ExecutionSession.estimate`:** These methods now accept a list of parameter dictionaries for batch execution, returning a list of results. The dedicated `batch_sample`, `submit_batch_sample`, `batch_estimate`, and `submit_batch_estimate` methods are deprecated — pass a list to the standard methods instead.
* **`variational_minimize` function:** Added a new public `variational_minimize` function for variational optimization of a cost function over the parameter values of a quantum program. Supports Hamiltonian and classical cost functions, `run_via_classiq`, and improved input validation. See the [SDK reference](/sdk-reference/execution/) for details.
* Added `slice(array, start, stop)` in `classiq.qmod.symbolic` as the Python alternative for [array slice expressions](https://docs.classiq.io/latest/qmod-reference/language-reference/expressions/#path-operators) on Python lists, analogous to `subscript`.
* **`classiq.print_diagnostics()`:** New function that prints a snapshot of the SDK version, Python environment, backend host and version, authentication status, and user ID - for easy inclusion in support tickets.

## Bug Fixes

* **Execution:** Sample jobs started with `execute()` now persist submitted-circuit metadata so `ExecutionJob.get_submitted_circuits()` matches the documented behavior.
* Studio - Light mode not saved for users preferences
* IDE - Synthesize button keeps showing and disappearing
* Fix synthesis of nested concatenations in control condition.

## API Changes

* The `theta` parameter of function `phase` was renamed to `coefficient`.
  The old name is deprecated and will no longer be supported starting on
  2026-05-04 at the earliest.
* Function `randomized_benchmarking` is deprecated and will no longer be
  supported starting on 2026-05-11 at the earliest.