Do you mean not going to /admin? If so, you should be able to get the current version by viewing page source. Right click on a blank part of your site and click view page source. A few lines from the top (here on Meta it’s line 10) you’ll see something like this:
<meta name="generator" content="Discourse 1.7.0.beta7 - https://github.com/discourse/discourse version 71fa9541fa65571249921bb47ac49e9ff2880726">
There’s the current version.