To be clear, it will be incompatible with GPLv2-only software. Projects which use the default GPLv2 license notice will be able to link with OpenSSL 3 without

To be clear, it will be incompatible with GPLv2-only software. Projects which use the default GPLv2 license notice will be able to link with OpenSSL 3 without problem, since the notice permits the software to be re-licensed under newer versions of the GPL. Also note that the old OpenSSL license was incompatible with both GPLv2 and GPLv3 (unless the project provided an exception for OpenSSL). So OpenSSL 3's license change increases compatibility with GPL software.