Just something I’ve been thinking about over the last few days - With GDPR coming into force shortly, password encryption of invoices will probably be used more and more - Obviously I know this won’t affect everyone as the majority of invoices/quotes wont need password protecting under the new rules but it may certainly effect some industries depending on the personal information transmitted in invoice/quotes.
What I am proposing is the possibility of setting a password in the client screen, this password can then be applied to all invoices/quotes that are generated for that client.
Currently you can do this on a global scale across the system but not a client-by-client basis with each client having a unique password for them (well without setting it manually each time an invoice/quote is generated). 
I was hoping to look into this but I really don’t think I’ll have time nor are my PHP skills quite up to scratch yet! 