libESMTP is licensed under the GNU Lesser General Public License and the example programs are under the GNU General Public Licence.
Support for libESMTP is available to all via the mailing list (currently off line, please refer to the home page for details). I try to answer all questions as quickly as possible, however as I work as a freelance embedded systems engineer it is not always possible to answer questions in a timely manner, so please bear with me.
Commercial users of libESMTP are strongly encouraged to purchase a commercial support contract, please contact support@stafford.uklinux.net for a quotation. I will always prioritise support requests from those with support contracts.
Users not purchasing commercial support are encouraged (but not obliged) to make a donation. By donating you are supporting the principle of open source software and you will help ensure continued development of libESMTP (well, something has to pay for the mortgage :-).