Stellar (XLM) is now running Protocol 28 on its mainnet, an upgrade code-named "Adapter" that went live on September 16, 2026, at 17:00 UTC. The activation opens a working path for migrating stored smart contract data on the network.

The change primarily targets developers building on Soroban, Stellar's smart contracts platform, together with the node infrastructure that underpins the network, rather than everyday wallet and application users.

What Protocol 28 "Adapter" Does

According to the report, the upgrade's central function is to provide a working migration path for data stored by deployed smart contracts. Rather than introducing new user-facing features, the protocol change addresses how contract data is handled under the network's upgraded rules, giving developers a defined process for moving stored data forward. For teams operating live applications, that defined process is what determines how their contracts' existing state carries forward under the network's upgraded rules.

Background: How Stellar Network Upgrades Work

Stellar's protocol evolves through network-wide upgrades that require coordination among validators. Ahead of a scheduled activation, node operators install software releases that support the new protocol version, and the upgrade takes effect once a supermajority of validators consents at the target time. Operators who have not upgraded in time risk falling out of consensus with the rest of the network. With the activation timestamp now in the past, that requirement turns operational: running software that supports Protocol 28 is what keeps a node processing the same chain as the rest of the network.

Soroban and Contract Data

Soroban brought native smart contract functionality to Stellar, going live on mainnet with Protocol 20 in February 2024. Contracts written in Rust store their state as entries on the Stellar ledger, which applications can read and update over time. Because deployed applications may depend on that stored state, protocol-level changes to data handling require a careful migration route — the that the "Adapter" upgrade is designed to fill, according to the report. The version number itself traces the arc: Protocol 28 arrives eight protocol versions after the release that activated Soroban, reflecting the sequence of numbered protocol versions the network has moved through since smart contracts went live on mainnet.

Stellar has operated since 2014 as a low-cost network for payments and asset issuance, with XLM serving as the native asset used to pay transaction fees and meet minimum balance requirements.

This report was first published by COINOTAG: Stellar (XLM) Mainnet Activates Protocol 28 "Adapter" With Contract Data Migration.