StartTLS encryption – which TLS versions are supported?

I am looking to set a third party application to authenticate with our domain. The application supports LDAPv3 and we have opted to use the start StartTLS extension to encrypt the credentials from the source host application towards the domain server.

Having said this, I am at a loss as to what TLS version is used in StartTLS. Given the older versions are less acceptable, we would like to opt to allow only the later version (1.2, 1.3) of TLS be accepted.

My question therefore is;

What TLS version is used/supported for StartTLS?