An update for your app is never a bad thing. An update is to improve your app whether the improvement it big or small. You should not keep an update a secret to your users. That means that there is more android app marketing for you to look forward to. Just like you would market your app before it is in stores, you should market your upcoming update the same way. Using means of social media you can announce an update and some of the new things that to be expected in it. The only type of update you shouldn’t announce is a bug fix.
You should announce the update a week or two before it will be released depending on the size of the update. Make sure that people are aware that there is going to be an update and that they are aware of some or all of the upcoming changes. If you got people excited for your app before the release then you will be able to get people excited about the upcoming update.
A price drop can happen for good and bad reasons with an app. A good reason would be lowering the price as a special event for a short amount of time then returning it to it’s original price. This could be a good idea around holidays such as Christmas because people will have more money to spend on apps. A bad reason is no one is buying your app so you have to drop your price in order to hope people will be more interested. Your app is only worth so much, you can still have a paid app you just need to find the marginal cost of it.
Complete list of Android App Marketing Lessons