If you’re using PowerPoint 2019 or Office 365, you have probably switched over to the 16×9 aspect ratio for your slides. OnePager 7.0.7 and later support this aspect ratio as well, which is useful if you’re in the habit of saving directly from OnePager to a PowerPoint file instead of doing a copy/paste.
To change your PowerPoint aspect ratio, go to Home > Chart Properties > Page Layout, and then change the PowerPoint Aspect Ratio setting from 4×3 to 16×9:
