How can I find what clients are using TLS 1.0

I need to keep the impact on the logs as small as possible until we can get logging going to a separate device. Worse, I do not have full access to the device and must submit my rule for deployment. The vendor does not support irules so it's a long process if something goes wrong. I tried the below but something is wrong:

when CLIENTSSL_HANDSHAKE { switch -glob [SSL::cipher version] { "1.0" - { { log local0. "[IP::client_addr] Old." }

}

The logs show the following: TCL error: tls_1.0_test - extra switch pattern with no body while executing "switch -glob [SSL::cipher version] { "1.0" - { log local0. "[IP::client_addr] Old." } }"

Where did I go wrong?