dns: unknown Checker type

When running a DNS check with the latest amd64 version, I get the error 'dns: unknown Checker type'. HTTP-Checks are working. Am I missing something here?

`
{
    "checkers": [{
        "type": "dns",
        "endpoint_name": "Testing DNS",
        "endpoint_url": "82.211.31.248:53",
        "hostname_fqdn": "www.google.de",
        "timeout": "2s"
    }]
}
`
