Cool, I was wondering what the Ukrainian missile engineers have been working on for the past year. Also from the article:
As a result, even with the currently limited inventory, Moscow will be targeted using the modified Neptune in the not-too-distant future, the official told us. That will add to the discomfort felt in the Russian capital, which has been repeatedly hit by Ukrainian drones.
To reach that roughly 290-mile distance from the Ukrainian border (and perhaps longer from a launch site), the payload will be reduced and the volume of fuel will be boosted. This is a common modification for cruise missile variants.