Learn English – Another phrase for “until this time”

I have a student (C1 level English) who has asked me for another way to say "Until this time" in an email. She wants to reference a meeting that she is having next month with an executive in another company in her complimentary close. As I don't believe my initial reaction – "um, we don't say things like that in emails in America…?" was sufficient, is there a resource that I can point her to that would provide a fairly exhaustive explanation of the rules of business email etiquette? She said the equivalent in her L1 – Czech – is "awhile," which did not do much to help answer her question. Stock phrases generally don't reference a specific time, obviously; which, she is aware, but wants to do something different…be original and inventive, I suppose. So what should I explain to her, and how – ?