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Featbit

v5.4.0 Breaking

This release includes 2 breaking changes for platform teams planning a safe upgrade.

Published 15h Productivity & Wikis
✓ No known CVEs patched
Read the diff → Tool health → What is this tool? →

✓ No known CVEs patched in this version

Topics

ab-test ab-testing asp-net-core ci-cd c# .net
+12 more
entitlement experimentation feature feature-flags feature-management feature-toggles progressive-delivery python release-as-code remote-config self-hosted typescript

Affected surfaces

auth breaking_upgrade

ReleasePort's take

Moderate signal
editorial:auto 12h

The "Data Sync" module is deprecated and its features are now part of the "End Users" module. Update integrations accordingly.

Why it matters: Deprecation requires migration before next release; affects Data Sync UI/API users.

Summary

AI summary

Updates Key Improvements, Miscellaneous, and https://github.com/featbit/featbit/releases/tag/5.3.2 across a mixed release.

Changes in this release

Breaking High

Migrates the `tags` parameter for tag‑management endpoints from URL query string to JSON request body.

Migrates the `tags` parameter for tag‑management endpoints from URL query string to JSON request body.

Source: llm_adapter@2026-06-03

Confidence: high

Breaking High

Requires database schema migration scripts for PostgreSQL and MongoDB to upgrade to this release.

Requires database schema migration scripts for PostgreSQL and MongoDB to upgrade to this release.

Source: llm_adapter@2026-06-03

Confidence: high

Breaking High

Deprecates the standalone "Data Sync" module, integrating its capabilities into the "End Users" module.

Deprecates the standalone "Data Sync" module, integrating its capabilities into the "End Users" module.

Source: llm_adapter@2026-06-03

Confidence: low

Feature Medium

Adds a new environment-level setting "Require Change Comment" that mandates comments before saving updates to feature flags or segments.

Adds a new environment-level setting "Require Change Comment" that mandates comments before saving updates to feature flags or segments.

Source: llm_adapter@2026-06-03

Confidence: high

Feature Low

Users are now identified globally by their email address, allowing a single account to access multiple workspaces.

Users are now identified globally by their email address, allowing a single account to access multiple workspaces.

Source: llm_adapter@2026-06-03

Confidence: high

Performance Low

Optimizes End User import with a redesigned intuitive UI.

Optimizes End User import with a redesigned intuitive UI.

Source: granite4.1:30b@2026-06-03-audit

Confidence: low

Performance Low

Enables exporting filtered lists of End Users instead of full dataset.

Enables exporting filtered lists of End Users instead of full dataset.

Source: granite4.1:30b@2026-06-03-audit

Confidence: low

Bugfix Medium

Fixes regression that prevented updates to Shared Segments introduced in v5.3.2.

Fixes regression that prevented updates to Shared Segments introduced in v5.3.2.

Source: llm_adapter@2026-06-03

Confidence: high

Full changelog

Key Improvements

Redesigned EndUser Import/Export

We have streamlined how you manage end-users by deprecating the standalone "Data Sync" module and integrating its
capabilities directly into the "End Users" module.

  • Optimized Upload: Features a redesigned intuitive UI for importing End Users.
  • Targeted Download: You can now export filtered lists of End Users instead of the entire dataset, allowing
    for more precise data portability.

Change Governance: Require Change Comments

To enhance compliance and auditability, we have introduced a new environment-level setting Require Change Comment.

  • When enabled, users are required to provide a comment before saving updates to feature flags or segments.
  • This is useful for production or critical environments that need to maintain a clean, accountable audit trail.

Miscellaneous

  • Users are now identified globally by their email address, allowing a single account to access multiple workspaces.
  • Resolved a regression introduced in v5.3.2 that prevented updates to Shared Segments.
  • Various UI/UX improvements.

Breaking Changes

Database Schema Changes

This release includes database schema changes. To upgrade, please apply the corresponding scripts for your database:

OpenApi Breaking Changes

The tags parameter for tag-management endpoints has been migrated from the URL query string to the JSON request
body
to adhere to REST best practices.

| Endpoint | Before (Query String) | After (JSON Body) |
|:-----------------------------------------------------|:-----------------------|:-----------------------------|
| PUT /api/v1/envs/{envId}/feature-flags/{key}/tags | ?tags=tag1&tags=tag2 | {"tags": ["tag1", "tag2"]} |
| PUT /api/v1/envs/{envId}/segments/{segmentId}/tags | ?tags=tag1&tags=tag2 | {"tags": ["tag1", "tag2"]} |

Migration: Update your API clients or automation scripts to pass Content-Type: application/json, remove the query
parameters, and include the array payload in the request body.

Full Changelog: https://github.com/featbit/featbit/compare/5.3.6...5.4.0

Breaking Changes

  • Database schema migrations required for PostgreSQL (v5.4.0.sql) and MongoDB (v5.4.0.js).
  • OpenAPI endpoints now require the `tags` parameter in JSON request body instead of URL query string.

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About Featbit

Enterprise-grade feature flag platform that you can self-host.

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Related context

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Earlier breaking changes

  • v5.3.4 Jwt__Key is now mandatory for HS256 signing.

Beta — feedback welcome: [email protected]