PreferKeepAlive property is not available anymore. How do I update my code?
PreferKeepAlive property has been removed in favor of KeepAlivePolicy in SBB 13. That's why you get the error.
To fix the project, you need to open the form with TElHTTPSClient in IDE and when you get a message that a property is not found, click Ignore.
KeepAlivePolicy is the enumeration:
TSBHTTPKeepAlivePolicy = public (kapStandardDefined, kapPreferKeepAlive, kapRelyOnServer, kapKeepAlivesDisabled);
* kapStandardDefined - keep-alive preferences are dependent on the chosen and negotiated version of HTTP protocol (1.0 or 1.1 or later).
* kapPreferKeepAlive - keep-alive is always requested.
* kapRelyOnServer - the client doesn't send Connection header and allows the server to choose the strategy
* kapKeepAlivesDisabled - send Connection: Close header and do not use keep-alives
Default value of the property is kapStandardDefined and we recommend keeping it this way.