I would like to recreate Judge Engine of Online Judge named HUSTOJ. However, HUSTOJ was released under the GPL-2.0 license.

I would like to release a new Judge Engine with AGPL-3.0.

I know that GPL-2.0 and AGPL-2.0 are incompatible licenses. However, I left the question because I do not know whether GPL-2.0 and AGPL-3.0 are compatible with each other, and whether I can set a license in this situation.

I would appreciate it if you know this.

1 Answer 1


Since you've examined the code of HUSTOJ and are creating a very similar work, you are legally preparing a derivative work of HUSTOJ.

Generally, no, you may not license a derivative of a GPLv2-licensed work under the GPLv3 or AGPLv3. See the GPL FAQ's compatibility matrix, which indicates the incompatibility (and note the statement of GPLv3 and AGPLv3 equivalency directly above the matrix).

However, since HUSTOJ is actually under GPLv2-or-any-later-version, you may receive HUSTOJ under the GPLv3 instead. GPLv3-licensed material can be included in an AGPLv3-licensed work.

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