Identify the unfair aspect with respect to the sentence extracted from an online Terms of Service:
```
airbnb may improve , enhance and modify the airbnb platform and introduce new airbnb services from time to time . 

```
. OPTIONS: ['Unilateral termination' 'Arbitration' 'Content removal'
 'Unilateral change' 'None' 'Jurisdiction' 'Limitation of liability'
 'Choice of law' 'Contract by using'].