Patreon PHP library version 1.0.0 moves on to Patreon's v2 API, which is not compatible with old v1 calls. It also removes Art4 JSON library. Therefore directly upgrading from older versions to 1.0.0 would break compatibility of your installation. APIv1 will deprecated some time soon after APIv2 come out of beta, so it's important to get your integration compatible with API v2. With API v2, you can only get access to the scopes you requested during authorization, and you need to ask for the data you want through the includes param.
If you were using Art4 library before, you can separately install it and feed the return from API calls to the Art4 library after getting it as JSON from this library. This will make your existing code that uses the Art4 library compatible. However note that you will need to track Art4 library updates and resulting compatibility issues yourself.