GPLv1

GPLv1, the first version of the GNU General Public License, was released by the Free Software Foundation (FSF) in 1989. It introduced the copyleft principle, aiming to keep software free for all users by ensuring that modified and redistributed versions remain under the same license.

Under GPLv1, redistribution of the program in source or binary form required that the recipient also receive access to the source code and the same licensing terms. The license prohibits adding restrictions beyond those it imposes and requires that downstream users obtain the freedom to run, study, modify, and distribute the software.

GPLv1 is largely superseded by later GPL licenses, notably GPLv2 (1991) and GPLv3 (2007). Many projects have migrated to newer versions, while some legacy code remains under GPLv1 terms. Unlike later versions, GPLv1 did not include an explicit "or later versions" clause, which in practice meant derivative works could be constrained to the original GPL version unless the code was relicensed.

Historical significance: GPLv1 established the copyleft model that became foundational for later free software licenses and the FSF's licensing ecosystem. It set expectations about source disclosure and the transfer of rights with redistributed code.

Limitations and evolution: Subsequent GPL versions added clarifications and new protections, including broader patent considerations and anti-tivoization provisions in GPLv3. These changes reflected evolving concerns in the free software community while preserving the core copyleft philosophy first articulated in GPLv1.