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

# Enabling Subblocks

> Learn about enabling Subblocks on an OP Stack chain.

<Warning>
  Subblocks replace Flashblocks. Flashblocks are no longer officially supported on OP Stack chains.
</Warning>

Subblocks are a private feature available only to OP Enterprise customers. If you are interested in becoming an OP Enterprise customer, [contact the OP Enterprise team](https://optimism.io/learn-more). See [this explainer on Subblocks](/op-stack/features/subblocks) for more details.