What does "all rights convey to the licensee" mean written in a contract?
The phrase "all rights convey to the licensee" may have different meanings depending on the context in which it appears in your contract and the contract as a whole. Generally, whatever rights are in that contract from the person allowing the license, the licensee (one who obtains the license) will have all those rights to conveyed to him or her.
Whether the rights conveying to the licensee are permanent or for a particular duration and for specific or products will depend on the contract's language and intent and usage.
Consider having your contract reviewed by an attorney in your state to determine if a) the laws of your state apply or that of another state or federal laws and b) to what extent the above phrase applies in your particular contractual arrangement.