Frontend

Languages

Policy: One of Specified Versions

Reasoning: Adopting new versions of these technologies may have substantial impact on shared community tooling or hosting providers

Chosen Technologies:

• JavaScript
• TypeScript

Build Tools

Policy: One of Specified versions

Reasoning: Adopting new versions of these technologies may have substantial impact on shared community tooling or hosting providers

Chosen Technologies:

• Node 22
• Yarn 1

First Party Libraries / Frameworks

Policy: One of Specified versions

Reasoning: The FOLIO community has previously adopted the policy that first party technologies must be synchronized across all modules within the system for easier support

Notes: These versions are often only decided upon in the latter states of the flower release process and may be subject to change even after this document is accepted

Chosen Technologies:

• Stripes 10.1 or greater

Shared Third Party Libraries / Frameworks

Policy: One of Specified versions

Reasoning: These technologies are fundamental to the operation of FOLIO. Modules supporting incompatible versions would lead to an non-operational system

Chosen Technologies:

• React 18.2

During Build Automated Testing

Policy: Unspecified versions

Reasoning: These technologies are only used for automated testing within the module. It is reasonable for the versions to vary between modules as the choice does not affect other modules or centralised community tooling

Chosen Technologies:

• Jest
  • should be 29 or greater
• RTL
  • should be 14 greater

Post Build Integration Testing

Policy: TBD

Reasoning: TBD

Chosen Technologies:

• Cypress 12.0*
• * Pending verification 

Backend

Languages

Policy: One of Specified Versions

Reasoning: Adopting new versions of these technologies may have substantial impact on shared community tooling or hosting providers

Chosen Technologies:

• Java 21 / JDK 21
  • Keycloak 25.0.0 release notes: "OpenJDK 17 support is deprecated in Keycloak, and will be removed in a following release in favor of OpenJDK 21."
  • Other software libraries used by FOLIO will also drop 17 support soon.
  • Java 21 more efficiently uses CPU resources (virtual threads, improved garbage collection, etc.) saving costs for implementers and devops.
  • New language features improve developer satisfaction and code quality/correctness.
  • Grails modules use at least Java 17
• Groovy (version determined by the version of Grails, below)
• OpenAPI (OAS) 3
  • See https://dev.folio.org/start/primer-oas/
• Go 1.27, see https://go.dev/doc/devel/release#policy:
  • Go 1.26 support period is ~ 2026-02 until ~ 2027-02, this doesn't cover the Trillium support period that ends Q2 2027
  • Go 1.27 support period is ~ 2026-08 until ~ 2027-08; FOLIO Go modules must migrate from Go 1.26 to Go 1.27 after Trillium general availability (GA, Q2 2026) as soon as Go 1.27 is available

Build Tools

Policy: One of Specified versions

Reasoning: Adopting new versions of these technologies may have substantial impact on shared community tooling or hosting providers 

Chosen Technologies:

• Maven 3.8 or later
• Docker
• Gradle - we should specify a version here... maybe 8.5 or greater based on the Java 21 requirement?
• Make - we should clarify this, e.g. with a version, is it gnu make, etc.?

First Party Libraries / Frameworks

Policy: One of Specified versions

Reasoning: The FOLIO community has previously adopted the policy that first party technologies must be synchronised across all modules within the system for easier support

Notes:

• These versions are often only decided upon in the latter states of the flower release process and may be subject to change even after this document is accepted.
• A first party library/framework needs to support only one of the versions allowed in the "Third Party Libraries / Frameworks" list.

Chosen Technologies:

• folio-spring-support 9.2 or greater
• folio-vertx-lib 3.5 or greater
• raml-module-builder 35.6 or greater
  • deprecated. Only existing FOLIO modules may continue to use raml-module-builder
• edge-common 4.11 or greater
• edge-common-spring 3.2 or greater
• folio-service-tools 5.2 or greater
• folio-s3-client 2.5 or greater
• folio-kafka-wrapper 3.5 or greater
• folio-custom-fields 2.5 or greater
• folio-liquibase-util 1.12 or greater
• folio-di-support 3.2 or greater

Third Party Libraries / Frameworks

Policy: Unspecified versions

Reasoning: These technologies are only used within a module. It is reasonable for the versions to vary between modules as the choice does not affect other modules or centralized community tooling

Notes: A first party library/framework may support only one of these versions.

Chosen Technologies:

• Spring Boot
  • 4.1 or later recommended (4.1 OSS support until 2027-06-30, 4.0 OSS support until 2026-12-31)
  • This requires using release candidate and milestone releases, at least during development time. This has been discussed for sunflower and trillium with the release management stakeholder group. (TODO: Migration guide, similar to FOLIO's migration guide for Spring Boot 4.0.)
• Spring Framework
  • 7.0 (required by Spring Boot 4.1) or later recommended (7.0 OSS support until 2027-06-30)
  • This requires using release candidate and milestone releases, at least during development time, see Spring Boot above.
• Grails 7
  • See https://grails.org/blog/2024-12-23-grails-7-m1.html (pre-release)
  • NOTE:  it looks like grails 7 will still be using an older version of spring boot.  Something to keep an eye on.
• Eclipse Vert.x 5
  
  • See https://vertx.io/blog/eclipse-vert-x-5-candidate-7-released/ (release candidate), Vert.x 5 is scheduled for the May 2025
• Lombok
  • Version compatible with Java 21 (1.18.38 or greater)
• AWS SDK for Java
  • version 2 (version 1 will reach end-of-support on December 31, 2025)
• MinIO Client library 8.5 or higher recommended https://github.com/minio/minio-java/tags
• Quarkus: The latest LTS release (3.32 LTS will get released March 2026)
  • See https://github.com/quarkusio/quarkus/wiki/Release-Planning and https://quarkus.io/blog/lts-cadence/ and https://endoflife.date/quarkus-framework
• Keycloak Admin Client: Latest minor release
  • Only latest minor release version is supported: https://github.com/keycloak/keycloak/security/policy#supported-versions
  • Minor versions bumps are backwards compatible, see https://www.keycloak.org/2024/10/release-updates
  • Previous release cadence:
    • 2025-04 – 26.2.0
    • 2025-01 – 26.1.0
    • 2024-10 – 26.0.0
    • 2024-06 – 25.0.0
    • 2024-03 – 24.0.0
    • 2023-11 – 23.0.0

During Build Automated Testing

Policy: Unspecified versions

Reasoning: These technologies are only used for automated testing within the module. It is reasonable for the versions to vary between modules as the choice does not affect other modules or centralized community tooling

Chosen Technologies:

• JUnit
  • 5 should be used, 4 (is in maintenance mode) may be used, however JUnit 5 vintage is preferred
• rest-assured 
• testcontainers

Post Build Integration Testing

Policy: TBD

Reasoning: These tests are run within a single repository, thus they must all use the same technology versions. However, I don't know if that version should be centrally controlled

Chosen Technologies:

• karate
• cucumber-reporting

Infrastructure

Policy: All of Specified Versions

Reasoning: These technologies are fundamental to the operation of FOLIO. Modules supporting incompatible versions would lead to an non-operational system. It may be necessary for modules to support multiple versions in the same module version e.g. in order to ease transition between infrastructure technology versions during system upgrades 

Chosen Technologies:

• Postgresql 16
  • See https://www.postgresql.org/support/versioning/
• OpenSearch 3 and Elasticsearch 9
  • OpenSearch release schedule and maintenance policy
  • Elasticsearch support policy, EOL dates, release history
• MSK/Kafka
  • Kafka 4.2 - See https://endoflife.date/apache-kafka and https://cwiki.apache.org/confluence/display/KAFKA/Future+release+plan; an open source minor version is supported for ~ 12 months; we expect 4.2 release ~ Feb 2026
  • MSK - See https://docs.aws.amazon.com/msk/latest/developerguide/supported-kafka-versions.html (we expect 3.8 to be supported by MSK ~Oct 2025)
• S3/MInIO - Current version of MinIO compatible with S3
• folio-kong
  • Latest version
  • Versioning approach for folio-kong and folio-keycloak
  • Kong Open Source Software (OSS) = Community Edition essentially only supports the most recent release, which is 3.10 as of 01 May 2025.  Releases (Enterprise Support Policy) typically happen every 3-4 months.
    • Long-term support policies are only available for Kong Gateway Enterprise.
    • OSS users are strongly encouraged to upgrade to the latest version to receive fixes and the newest features.
  • Rough prediction based on the 3-4 mo. release cadence:
    • Dec `24 - 3.9
    • Mar `25 - 3.10 (current latest)
    • Jun `25 - 3.11
    • Sept `25 - 3.12
    • Dec `25 - 3.13
    • Mar `26 - 3.14 → folio-kong 3.14.* built on Kong 3.14.*
• FOLIO Keycloak
  • Latest version
  • Versioning approach for folio-kong and folio-keycloak
  • See https://github.com/keycloak/keycloak/security/policy#supported-versions: "Supported Versions: Depending on the severity of a vulnerability the issue may be fixed in the current major.minor release of Keycloak, or for lower severity vulnerabilities or hardening in the following major.minor release."
  • See https://github.com/keycloak/keycloak/discussions/19937: "the latest version is the only actively supported version. Therefore any version that is not the latest version is technically end-of-life."
  • See https://www.keycloak.org/2024/10/release-updates
    

    • ... after Keycloak 26.0 is released there will be some changes to how Keycloak is being released:

      • Keycloak server will have 4 minor releases every year, and a major release every 2-3 years

      • Keycloak client libraries will be released separately. The latest client library release will support all currently supported Keycloak server releases

  • Rough prediction based on the above:
    • Jan `25 - 26.1
    • Apr `25 - 26.2
    • Aug `25 - 26.3
    • Nov `25 - 26.4
    • Jan `26 - 26.5 → folio-keycloak 26.5.* built on Keycloak v26.5.*

Policies

Policies should use the language described in RFC-2119

Technology Version Policies

These policies define guidance for module developers on which versions of technologies are reasonable to use by a module version targeted for a given flower release

One of Specified Versions

When one or more versions are provided for a technology, the modules must use / work with / support one (or more) of the specified versions

For example, if Java 17 and 21 are supported, a module a may choose to support either 17, 21 or both

All of Specified Versions

When one or more versions are provided for a technology, the modules must use / work with / support all of the specified versions

For example, if Postgresql 14 and 16 are supported, a module must work with both 14 and 16

Unspecified Versions

When no versions are provided for a technology, the module should use the latest supported version where possible. Optional guidance specific to the technology may be provided within the document

Support period

Technology versions must support the full Umbrellaleaf support period that ends around Q2 2027: Umbrellaleaf will be released in Q2 2026 and will be supported until Wisteria (R1 2027) gets released around Q2 2027 (based upon assumption that future releases will follow a similar cadence to previous releases), see FOLIO support policy.

^* Current best guess