With advances in technology, solicitations now tend to occur even earlier in the patent and trademark application process than in the past. It is also common for solicitations to pertain to renewal or other "maintenance" issues for registered trademarks and granted patents. There are even solicitations from foreign registries directed to U.S. recipients.
Altough such solicitations are not official correspondence from any government agency, they are often presented in the style of an official-looking invoice, even though they merely constitute a contractual offer, at best. Recipients should therefore take caution as they are not obligated to participate or pay the indicated amounts. Even worse, some solicitations are bold enough to appear as if they are issued by an official government agency, in some cases, very similar sounding to the real thing. As seen, below, this has prompted the U.S. PTO to issue a recent notice on this subject: