File 01 — The Licence Fights
Four major relicensing events, four forks, and the boundary the OSI holds.
Photo: Myburgh Roux / PexelsIn August 2023 HashiCorp relicensed Terraform under the Business Source Licence, citing competitive use by managed-service providers.
![Grid of random slashes, dashes and vertical bars under the label "multimodal model [v2]"](/img/guide-redis-rsalv2-valkey.jpg)
Photo: Google DeepMind / PexelsRedis Ltd moved Redis from BSD to the RSALv2 and SSPL dual licence in March 2024, ending a decade of permissive terms.
Photo: Elasticsearch logo · Wikimedia CommonsElastic moved Elasticsearch and Kibana to the SSPL in January 2021, prompting AWS to fork both as OpenSearch.
Photo: Pixabay / PexelsMongoDB wrote the Server Side Public Licence in 2018 and submitted it to the Open Source Initiative for approval; the OSI declined to approve it, and the SSPL has remained outside the canonical approved-licence list.
Photo: Sharad Bhat / PexelsThe three most widely used licences impose different obligations on downstream users, and the gap between MIT's permissiveness and GPL's copyleft has driven real corporate decisions about which projects to adopt.
Photo: Pixabay / PexelsA Contributor Licence Agreement transfers or licenses copyright to the project steward, which is why HashiCorp and Elastic could relicense unilaterally while OpenTofu and OpenSearch required forks: they lacked consolidated copyright.
Photo: Digital Buggu / PexelsWhen Sentry moved to the Functional Source Licence in 2023, it promoted the term 'fair source' as a category distinct from both open source and proprietary software.