Redistribution - Am I allowed to redistribute a modified copy of the SMF software

Yes. SMF 2.x is released under a BSD License. This means that redistribution and use in source and binary forms, with or without modification, are permitted, provided that the following conditions are met.

Please note that according to statement 3 of the BSD License if you choose to distribute a modified copy of Simple Machines Forum, you cannot use the names Simple Machines Forum or Simple Machines. You also cannot use the names of its contributors to endorse or promote the derived product without specific prior written permission.

Please read The Simple Machines 2.0+ License for further information.

No. You cannot redistribute a modified or a non-modified copy of SMF. You are allowed to create a "mod" to reproduce modifications you make to the software and distribute the mod package.

Please read The Simple Machines 1.0 and 1.1 License for further information.