To answer your 2.1 question, here is what iRobot
said about it:
engineers are constantly working on Roomba to improve the product and Roomba 2.1 is our latest robotic vacuum cleaner.
What makes Roomba 2.1 better?
's new AWARE robotic intelligence provides greater room coverage.
2. A redesigned cleaning system with improved brushes which improves brush contact with floors and gives you better cleaning efficiency.
3. Easier cleaning.
4. Improved robot durability.
5. New brush bearings resist hair build up.
6. New Software that improves Roomba's cleaning efficiency.
7. Improved charge circuitry to provide longer overall battery life.
8. Improved side brush design.
9. Improved balance of the vacuum impeller.
10. Improved vacuum bin contacts.
11. Improved wire routing for system durability.
12. Optimized sensors for system efficiency.
13. Overall 20 enhancements to both hardware and software have been incorporated in Roomba 2.1.
If you have any questions about Roomba 2.1 please contact customer support at 1-877-855-8593."
Hope this helps you.