SIMBA Protocol Changes for Securities and FX Markets, Rel. 30.11.26

We inform you of changes to the SIMBA binary protocol for the Securities and FX Markets, scheduled for implementation on November 30, 2026, as part of the planned release of the Securities and FX Markets system.

PLEASE NOTE that changes to the SIMBA protocol for the Securities and FX markets are not backward compatible and require modifications to client-side software.

In the SecurityDefinition message, the field type for LotDivider will be changed from uInt16 to uInt32.

The updated message schema sbe_asts_md is available on the MOEX FTP server: https://ftp.moex.com/pub/SIMBA/ASTS/schemas/release28_11_2026/.

The document listing changes to the Securities and FX Market systems has been updated.