Then you are using a VERY old version of Indy and really should upgrade to the latest.
Most likely NOT 10.6.2.0 specifically, but some later version of 10.6.2.x, where x was unknown at the time your copy of Indy was compiled.
Specifying multiple SSL/TLS versions will automatically enable sslvSSLv23 internally. That is the wildcard that actually handles version negotiation at runtime. You should not be specifying sslvSSLv23 explicitly at all.
Makes sense, because nobody uses SSL v2.0 and v3.0 anymore, as they are no longer secure. Don't use anything less than TLS v1.0, but even that is being phased out of modern servers nowadays, so you really need TLS v1.1 and v1.2 as an absolute minimum.
If that weren't the case, the other values (sslvSSLv2, sslvSSLv3, sslvSSLv23, and sslvTLSv1) wouldn't be compiling, either.