Question about iRobot Roomba i7+

Hey :)
Thanks for your question. With a threshold height of up to 1.6cm Roomba models will have no problems, with higher thresholds like yours, which are about 3cm high, it depends somewhat on the circumstances. At iRobot there is the possibility to test all current models in advance for free. This way you can make sure that the device meets your expectations and whether there are any problems with door thresholds. If this is the case, it is possible to place small ramps in front of the Roomba, as users in old flats have done. You can buy these in DIY stores and they work perfectly.
For a test unit you can contact us directly. You can reach us by phone at +41 62 746 06 74 or by e-mail at service@irobotics.ch.
Best regards,
Your iRobot Team

The maximum height of a threshold that all Roomba models can cross when performing a cleaning cycle is 1.6cm.
CONCLUSION: Your thresholds of 3cm are too high.

No, in my experience with this robot, 3 cm is far too high.

The maximum height of a threshold that all Roomba models can cross when performing a cleaning cycle is 1.6 cm.
Conclusion: Your 3 cm thresholds are too high.