v4.0.0

Welcome to Prebid Server 4.0!

This is a major release, so please read through the release notes. If you are already running rc1, there is no need to upgrade as there are no code changes between rc1 and final release.

The release notes only list a summary of changes. There are more details about breaking changes in individual PRs.

This release primarily focuses on infrastructure upgrades and deprecations. This means that host companies should review their configuration as there were some changes.

Major Technology Highlights

• Java 25
• Spring Boot 4.0
• Vert.x 5.0

Major Feature Highlights

• Dependencies: Bump Java, Vertx and Spring Boot to the latest major version (#4520)
• Core: Enable strict RFC 3986 URL compliance by default (#4581)
• Core: Add special Gzip decompression handler (#4498)
• Core: Make vendor-id mandatory for aliases (#4533)
• Core: Add Secondary Bidders support (#4331)
• Core: Update cookie sync to use bidder name instead of cookie family (#4464)

Potentially Breaking Changes

• Magnite adapter: Rebrand Rubicon adapter into Magnite adapter (#4573)
  • Rename rubicon leftovers to magnite (#4580)
  • Important - this update requires a configuration change because magnite is now a material bidder and rubicon is an alias.

Old config:

adapters:
  rubicon:
    aliases:
      magnite: ~

New config:

adapters:
  magnite:
    aliases:
      rubicon: ~

• RadiantFusion adapter: Rename radianfusion to radiantfusion (#4579)
• Bidgency adapter: Rename bidagency to bidgency (#4578)
• ResetDigital adapter: Switch to OpenRTB (#4385) (#4463)
• Intertech adapter: Remove adapter (#4433)
• DXKulture adapter: Remove adapter (#4434)
• Adsinteractive adapter: Remove adapter (#4567)
• Telaria adapter: Remove adapter (#4566)
• Modules: Rename Prebid modules and align hook suffixes across existing modules (#4427)
  • Important - Prebid-maintained modules are renamed to include pb prefix. This will require host companies to update module execution plans.
  • Important - module hooks had a maintenance pass to align the naming. Now all module-declared hooks contain the hook suffix. This will require host companies to update module execution plans.
• Core: Deprecate Video endpoint (#4555)
• Core: Improve and validate bidder adapters by migrating to Vert.x UriTemplate (#4444)
  • Important - bidder URLs now use single curly brackets ({}) for placeholders instead of double curly brackets ({{MACRO}})
• Core: Improve and validate user syncs by migrating to Vert.x UriTemplate (#4569)
  • Important - cookie sync URLs now use single curly brackets ({}) for placeholders instead of double curly brackets ({{MACRO}})
  • Vert.x Template: Fix bugs (#4568)
• Core: Make SetuidHandler bidder lookup case-insensitive (fixes regression introduced in #4464
• ) (#4557)
• Core: Allow duplicate cookie family names (#4316)
  • Core: Allow duplicate cookie family names for priority sync (#4572)
• Core: Rename http-client.use-compression to http-client.use-decompression (#4574)
• Core: Handle GVL deletions (#4519)
  • Important - this introduces a new mandatory configuration property. This property can point to the same place as TCFv2 vendorlist cache directory, but can also be a separate directory.

gdpr:
  vendorlist:
    live:
      startup-cache-dir: /path/to/latest/gvl

• Metrics: Update setuid metrics to use bidder name instead of cookie family name (#4571)

What’s Changed

• Microsoft: New adapter (#4310)
• Modules: Add HTTP method support to module execution plan configuration (#4372)
  • Core: Add http_method field to ExtRequestPrebidServer (#4378)
• Core: Remove deprecated PAAPI-related code (#4514)
• Core: Remove obsolete/unneeded fields from requests to bidders (#4332)
• Core: Remove unused support-cors usersync config (#4429)
• Logger: Replace static logger sampling with a configurable one (#4408)
• Housekeeping: Remove old unused PG classes (#4432)
• Tests Housekeeping: Replace MockServer with WireMock (#4390)

Contributors

@And1sS, @CTMBNara, @Lightwood13, @Net-burst, @marki1an and @osulzhenko