What is the difference between LGPL-2.1 and LGPL-3.0?

Short answer: Shipping an app that links an LGPL-3.0 library: Yes.

Both are weak copyleft library licenses; LGPL-3.0 is written as extra permissions on top of GPL-3.0 and inherits its patent and anti-tivoization terms.

Shipping an app that links an LGPL-3.0 library: Yes

License: GNU Lesser General Public License v3.0 (LGPL-3.0-only, curated)

• Every use you described is granted by LGPL 3.0, and nothing you described is prohibited.

Duties: attribution, license_notice, share_alike, source_disclosure

Duties and notes compared

• LGPL-2.1-only: duties attribution, license_notice, state_changes, share_alike, source_disclosure. The copyleft duties apply to the library and modified versions of it, not to an application that only links to it (section 5). Each recipient receives a license from the original licensor; sublicensing is not allowed (section 10).
• LGPL-3.0-only: duties attribution, license_notice, share_alike, source_disclosure. The copyleft duties apply to the library and modified versions of it, not to an application that only links to it.

Combined in one work: needs_review.

Context

• Devices that ship LGPL-3.0 code must let users install modified versions of the library (installation information).

Sources

• GNU LGPL v3.0
• GNU LGPL v2.1

Check it yourself (free, no key)

{
  "tool": "check_license",
  "arguments": {
    "license": "LGPL-3.0-only",
    "intended_use": {
      "commercial_use": true,
      "redistribution": true
    }
  }
}

Computed from Rightshold's license profiles; not legal advice. Updated 2026-10-23. JSON · Markdown