版本不对的原因。
具体在10.5.9下修改此参数即可解决问题。
loadfunction() has an acritical parameter. it is set
to true by default, but can be set to false for individual functions (and
currently is false for tls 1.1+ and dtls functions). you can patch
idsslopensslheaders.pas to set acritical to false for the missing sslv2
functions. as long as you never use sslvsslv2 in tidssliohandlersocketopenssl,
you should be fine. i will add this to the todo list for a future indy
release.