{
  "question": "What is the difference between LGPL-2.1 and LGPL-3.0?",
  "slug": "lgpl-2-1-vs-lgpl-3-0",
  "url": "https://www.rightshold.com/answers/lgpl-2-1-vs-lgpl-3-0",
  "short_answer": "Shipping an app that links an LGPL-3.0 library: Yes.",
  "framing": "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.",
  "checks": [
    {
      "label": "Shipping an app that links an LGPL-3.0 library",
      "license": "LGPL-3.0-only",
      "license_name": "GNU Lesser General Public License v3.0",
      "intended_use": {
        "commercial_use": true,
        "redistribution": true
      },
      "verdict": "permitted",
      "answer": "Yes",
      "findings": [
        "Every use you described is granted by LGPL 3.0, and nothing you described is prohibited."
      ],
      "duties": [
        "attribution",
        "license_notice",
        "share_alike",
        "source_disclosure"
      ],
      "curation": "curated",
      "official_text": "https://www.gnu.org/licenses/lgpl-3.0.html"
    }
  ],
  "compatibility": {
    "licenses": [
      "LGPL-2.1-only",
      "LGPL-3.0-only"
    ],
    "verdict": "needs_review"
  },
  "compare": [
    {
      "license": "LGPL-2.1-only",
      "duties": [
        "attribution",
        "license_notice",
        "state_changes",
        "share_alike",
        "source_disclosure"
      ],
      "notes": [
        "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)."
      ]
    },
    {
      "license": "LGPL-3.0-only",
      "duties": [
        "attribution",
        "license_notice",
        "share_alike",
        "source_disclosure"
      ],
      "notes": [
        "The copyleft duties apply to the library and modified versions of it, not to an application that only links to it."
      ]
    }
  ],
  "context": [
    "Devices that ship LGPL-3.0 code must let users install modified versions of the library (installation information)."
  ],
  "sources": [
    {
      "title": "GNU LGPL v3.0",
      "url": "https://www.gnu.org/licenses/lgpl-3.0.html"
    },
    {
      "title": "GNU LGPL v2.1",
      "url": "https://www.gnu.org/licenses/old-licenses/lgpl-2.1.html"
    }
  ],
  "check_it_yourself": {
    "mcp": {
      "tool": "check_license",
      "arguments": {
        "license": "LGPL-3.0-only",
        "intended_use": {
          "commercial_use": true,
          "redistribution": true
        }
      }
    },
    "rest": "POST https://www.rightshold.com/v1/licenses/check"
  },
  "computed_from": "Rightshold license profiles at render time; not legal advice",
  "updated": "2026-10-23"
}