Ask HN:Open source project using a registered trademark?

I am the developer and maintainer of open source project SwiftWeather (https://github.com/JakeLin/SwiftWeather). And I received an email from Swift Weather Company (www.swiftweather.com). They said they are the owner of U.S. Trademark Registration No. 4175355 for the mark SWIFT WEATHER. And the open source project is in direct conflict with their federal trademark rights. They requested me to change the name of this application and refrain from further use of their mark for any purpose thereafter.

I don't earn any money from this project (even one cent ). I am seeking advice to handle this issue. I have some potential ideas as below:

1. Modify the README.md (https://github.com/JakeLin/SwiftWeather/blob/master/README.md) file to add some description of Swift Weather Company. Some of the open source projects have sponsors in their README.md. We can do something similar but without charging Swift Weather Company. That can help Swift Weather Company attract more user to use their services.

2. Rename the project. Because there are some external links to the current project from other GitHub projects, blog posts etc. It may cause some problem with the redirection. If we need to rename the project, there some options:

  * SwiftWeatherApp: I am not sure is it same as the current project name SwiftWeather because it still has SwiftWeather within the name.

  * SwiftiOSWeather: It is a little bit weird for me by adding iOS in between. But that should be different from the SWIFT WEATHER trademark.

  * Any better name?

I prefer the first option but am seeking more advice to create a win-win situation. Thanks.