> 1) should i use the latest version of HDSentinel?
Yes. Generally the compatibility pages reflect the status with the latest version of the software and generally the detection of devices improve with newer and newer versions.
It is possible that newer devices (for example such dual drive devices, RAID controllers, newer NVMe SSDs etc...) are not yet recognised in older versions - but work perfectly with newer/newest versions.
So I'd recommend to check with the latest 5.01 version and if things are not perfect or the status is partial/missing, I'd try the latest possible beta version (5.01.5 now) as generally updated betas always have improvements for particular devices - so it is possible that things will be better with it.
> 2) "Send test report to developer option" means HDSentinel has inner email server?
> as i'm mostly behind router and firewalled connection, this means configuring the options in hdsentinel, also changing router and firewall settings
I can confirm that there is no need to change any setting or so.
No, it is not sent in e-mail (so no need to have any e-mail configuration or so): the software automatically sends via HTTP connection.
I mean that if (from your browser) you can access www.hdsentinel.com then the report sending should work - without changing any settings (maybe you'd only need to enable network access in the firewall when asked).
> 3) can it be done easier?
for me, i mean. save report file, and attach it in webmail and voilaa?
The easiest way is to use the Report menu -> Send test report to developer option, as then you can immediately send
If you prefer, you can create, save and send: please open Configuration -> Send test report page and there it is possible to create test report, save to file - and you can send the created file as attached to a mail.
> 4) is it different, what connection i use: usb2/usb3/esata?
Generally there should be no difference - but in some situations, yes, there can be difference, depending on the USB (or eSATA) controller.
I'd suggest to please try as you prefer to use (for example eSATA) - and if things are not perfect, you may attempt to check on USB, just to verify if things are different in any ways. This may reveal (for example) if the eSATA controller is not really port-multiplier compatible.