till vs. until in "from Apr. 21st till/until Apr. 28th" [duplicate]
Solution 1:
Till and until are completely interchangeable. To also works here.
Just use an en dash between numbers for ranges: “Apr 21–28”. Do not use a hyphen (-). Do not use an em dash (—). Use an en dash (–) only.
Solution 2:
You need something to separate the two dates. You can't just say, "from April 21st April 28th".
The most common thing to put between them is the word "to".
If you're writing full sentences, like "We agreed that we would schedule the convention to occur from ...", I think you need to put a word between the two dates, like "to" or "until" or "through". But if you're writing a title or a heading, you can condense it to "April 21 - 28". Or "Apr 21-28" if you're pressed for space, like in a column heading.