Support for Robotic Vacuum cleaners

My robotic vacuum cleaner shows error E21, warning triangle and Play button are blinking

How to remove or replace the robotic vacuum cleaner's batteries?

How to prepare the robotic vacuum for long idle periods?

Can I use the robotic vacuum if I have a pacemaker?

My robotic vacuum cleaner shows error E40 or E42

My robotic vacuum cleaner shows error code E17

Will the clock settings be saved after exchanging batteries or when the robotic vacuum cleaner was not charged for a longer time period?

Will I need to use another vacuum cleaner apart from the robotic vacuum?

Where can I buy accessories (filters, brushes, battery packs, spare parts) for my robotic vacuum?

When to change the robotic vacuum's batteries