-m 7000 = Fortigate (FortiOS) was never implemented in oclHashcat/cudaHashcat and therefore is currently also not available in hashcat 3.10 (since hashcat 3.00 basically improved oclHashcat to support OpenCL-compatible CPUs too and is therefore not a direct successor of hashcat-legacy).
You can download hashcat-legacy and use your CPU to crack those hashes: https://github.com/hashcat/hashcat-legacy/releases (or you could compile hashcat-legacy from git if you want).
If you really insist that this should be implemented into hashcat 3+, you should open a github issue (but not sure how many requests for this algorithm we get.... therefore it might at least take some time until somebody implements it into hashcat 3+, if at all).
You can download hashcat-legacy and use your CPU to crack those hashes: https://github.com/hashcat/hashcat-legacy/releases (or you could compile hashcat-legacy from git if you want).
If you really insist that this should be implemented into hashcat 3+, you should open a github issue (but not sure how many requests for this algorithm we get.... therefore it might at least take some time until somebody implements it into hashcat 3+, if at all).