After doing some tests on Windows 7 with Wireshark Network Analyser, I believe this is what's happening...
PE6 checks for updates at
www.picaxe.com/PE6 using HTTP Protocol. The server replies with "HTTP 301 Moved Permanently" and redirects the request to the following secure URL
https://picaxe.com/software/picaxe/picaxe-editor-6/
On 25/06/2021 I corrected the links in this post due to misreading Wireshark during my initial analysis (everything else in this post is the same).
PE6 now tries to communicate using Transport Security Layer 1.0 (TLS 1.0) but this fails and the server replies with a "
Fatal protocol error" message.
PE6 tries the TLS 1.0 request for a second time and this also fails.
The PE6 error message
"unexpected error occured on send" is slightly misleading as Wireshark clearly shows the URL request being sent to the server.
I also tested the URLs on a web browser with different level of TLS enabled within the browser. I found the http
s pages would only load when TLS 1.2 was enabled.
So the problem seems to be that PE6 doesn't have the ability to communicate with the server using the TLS 1.2 Protocol.
I'm not entirely sure what should happen when the "check for updates" feature (presumably) worked in the distant past. Did it just offer a new download within PE6, or did it open a web browser on the PE6 download page???
Regards
Jack