GOG might have embraced indies and AAAs to give its online catalogue some grunt, but it's still dedicated to getting retro classics running on modern platforms. With Windows 10 on the horizon, the company has been working to make sure older (and some newer) titles are good to go for Microsoft's next operating system.
A news post on GOG's website outlines the step it's taken to be "as ready as can be". Fortunately, even with its quality assurance team "at full capacity", it hasn't run into that many issues, which is either a testament to GOG's preparedness, or that Windows 10 isn't completely flipping the table when it comes to backwards compatibility.
The post also mentions that GOG's "entire library" has been undergoing testing, so it's not just the DOSBox-wrapped games that have been getting attention.
For games that that disagree with Windows 10, GOG states that patches will be made available as early as possible and those running the company's Galaxy client will receive the updates automatically.