I wish I had a satisfying answer to give, but we've been getting small sporadic shipments of the Versa pumps for a while now. My best advice would be to hit that 'notify me when in stock' button on the product pages and check back frequently.
Of course, if you need something more quickly, we do have some alternative options, depending on what you're using this dosing pump for. For example, the Kamoer FX-STP is a great option if you need something continuous duty, while the X1 pumps, Red Sea Reefdose, GHL, and other dosing pump options on the site work great for dosing two part or other additives periodically throughout the day.