Historically, the ENA have assigned versions only to major XML schema releases (latest major version is 1.5) while continuing to make small incremental changes to the schemas.
Recently, the ENA has improved on this by incrementing schema versions after all schema changes.
Latest schema versions continue to be available from:
ftp://ftp.sra.ebi.ac.uk/meta/xsd/sra_1_5
The deployed schema version is now included in a comment after the XML declaration, for example (latest version is 1.5.20):
<?xml version="1.0" encoding="UTF-8"?>
<!-- version:1.5.20 -->
The schema versions are also available from GitHub: https://github.com/enasequence/schema
Latest schema versions are available from the master branch: https://github.com/enasequence/schema/tree/master/src/main/resources/uk/ac/ebi/ena/sra/schema
Production releases are tagged with the version number: https://github.com/enasequence/schema/releases
Please note that the GitHub repository is structured for generating Apache XMLBeans (now retired Apache project) and that we may change the structure in the future.
Please also note that while many of the ENA XML schemas are similar to the ones used by NCBI and DDBJ they are not identical and the versioning differs between us and NCBI.