I'm having trouble updating /notify in the latest beta version of mIRC (7.68.3357) and some earlier ones.
But only on two of these networks. Probably a problem with the misread WATCH command for mIRC.

Reproduce:
1. Connect to irc.genscripts.net or cs1.coders-irc.net.
2. Connect another client to the same server.
3. Add the client from connection 2 to connection 1 to /notify.
4. Update /notify in connection 1.

You can see the correct value. Connection 2 is online.

5. Put connection 2 into /away mode.
6. Update /notify in connection 1.

Now you will see connection 2 is in offline mode. But it is still there - only in away mode. You can switch connection 2 back from /away mode and update /notify in connection 1. The user will be back online.

Thanks for your bug report. I have not been able to reproduce any issues by following your steps so far.

Note that the purpose of the notify list is to show whether a nickname is on IRC. It has nothing to do with a user's away state.

Understand. But for me notify list or notify category on "Treebar" won't show if this user is online when his got set /away mode on these servers.

Right, I see what's happening. InspIRCd 3 uses another numeric for the WATCH list, numeric 609, to show that a notify user is away. So a client now has to check for both numerics 604 and 609 to know whether a nickname is on IRC. This will be added to the next beta.

I will also be adding support for WATCH numerics 597, 598, and 599:

Unfortunately, it looks like InspIRCd 3 is not covering all of the cases for these events.

For example, if nickname A is on IRC and has set an /away message, if they change to nickname B, and nickname B is on your WATCH list, your client will receive numeric 600 to let it know the nickname is on IRC, as expected. But your client will not receive a numeric to let it know the nickname is away.

The only way to resolve this would be for InspIRCd to either send numeric 598 after 600, or to use a new numeric instead of 600... unfortunately, a new numeric would break the WATCH list for clients again, in the same way that adding numeric 609 to replace 604 did.

I don't know that much but I understood a lot. Wouldn't it be better if mIRC used /ison command in notify for InspIRCd 3?

WATCH was specifically created to replace ISON, and is superior to it in every way. If WATCH is available, it should be used. That said, mIRC also supports MONITOR, which is an update to WATCH.

It now works better than I expected. Heartfelt thanks to.