Not really sure the best way to put the subject title, but consider the following process done I ran in the demo company on a BV2017 install and a BV2018 install:
1. Create a new customer with no email
2. Go to order entry and post an invoice to new customer (#1)
3. Go back to the Customer screen, add a main email address, and change the form settings to form and email, and save.
4. Create and post a new invoice in order entry (#2)
5. Back in the Customer screen, bring up the Sales history and open both invoices
In BV2017, the option to email the invoice is available for both invoices. In BV2018, the email option is only available in the #2 invoice, created after an email address was added, but not invoice #1.
Now I understand that there's two tables for address here, ADDRESS and HISTORY_ADDRESS. Addresses for the Customer module are stored in ADDRESS, and when posting an invoice a snapshot of that address is taken and stored in HISTORY_ADDRESS. If the customer address later changes, the bill to/ship to address in the invoice history doesn't change with it because it's in HISTORY_ADDRESS.
So I thought maybe BV2018 changed things around so that the option to email an invoice from history is tied to the history, so if there was no email at the time it stays greyed out. This isn't entirely the case though, as I did a 3rd test:
6. Change the customer email address
7. post a new invoice in order entry (#3)
Now looking in this customer history, the email option is available for invoice #2 and #3 but not #1. However when I email invoice #2 and #3, it pulls the email address from the ADDRESS table and both go to the same email address updated in step 6.
Does that all make sense? I had one client bring this up with me today, who often gets customers who provide an email address later but then want their older invoices emailed to them. I upgraded over the weekend, so on Friday he could send these with one click, but today the button is greyed out and he has to go through the manual export option for each one.
Is this something that can be corrected? If BV is going to email history from the address saved in the main ADDRESS table, then the button shouldn't be greyed out if there's no email in HISTORY_ADDRESS. And I did verify this, with invoice #1 I went into pervasive SQL and added an email to the HISTORY_ADDRESS bill to line, and that was enough to switch the option back on in BV.