Fix instructions for backend spec [skip ci]

Author: stefanradev93

README.md

@@ -76,7 +76,7 @@ Note that BayesFlow **will not run** without a backend.
 
 If you don't know which backend to use, we recommend JAX as it is currently the fastest backend.
 
-Once installed, [set the backend environment variable as required by keras](https://keras.io/getting_started/#configuring-your-backend).
+As of version ``2.0.7``, the backend will be set automatically. If you have multiple backends, you can manually [set the backend environment variable as described by keras](https://keras.io/getting_started/#configuring-your-backend).
 For example, inside your Python script write:
 
 ```python
@@ -97,8 +97,6 @@ Or just plainly set the environment variable in your shell:
 export KERAS_BACKEND=jax
 ```
 
-This way, you also don't have to manually set the backend every time you are starting Python to use BayesFlow.
-
 ## Getting Started
 
 Using the high-level interface is easy, as demonstrated by the minimal working example below: