No, the IQOS 3 DUO Pocket Charger is not compatible with previous IQOS versions.
If you insert the IQOS 2.4 PLUS Holder into the IQOS 3 Pocket Charger, the Holder won’t fit because they’re different sizes.
If you accidentally insert the IQOS 3 Holder into the IQOS 2.4 PLUS Pocket Charger, the Pocket Charger lights will start blinking, but the Holder won’t charge.
Make sure you always charge your IQOS 3 Holder with the IQOS 3 Pocket Charger.

Your IQOS 3 DUO device doesn’t need to be fully charged to work but for the best experience, we recommend you fully charge the device before you use it for the first time. 
If your IQOS 3 DUO device is fully charged, you can use it up to 20 times before you need to recharge.

It takes approximately 120 minutes (two hours) to fully charge your IQOS 3 DUO Pocket Charger from an electrical outlet, using the IQOS AC Power Adaptor and USB cable.

Simply press your IQOS Pocket Charger button for one second. The LED lights will show the charge level – one light means your device has low battery and you need to charge it, four lights mean the device is more than 75% charged and ready to use.

IQOS 3 DUO has our fastest and most powerful Holder yet.
We’ve designed it around your needs to help you use IQOS your way. IQOS 3 DUO offers two consecutive uses without needing to recharge. And one of the benefits is a faster charge time. As long as it’s fully charged, it’s at least 2 minutes and 20 seconds faster than the IQOS 2.4 PLUS, and at least 1 minute 40 seconds faster than the IQOS 3*.
It also has the IQOS ProtectPlus System built in, for better protection and reliability, as well as a NFC chip which makes registering your device and accessing your IQOS account easier than ever.
*provided IQOS 3 DUO Holder is fully charged the first time or when fully depleted; and applicable for charging IQOS 3 DUO Holder from 0 to 1 use. It may depend on conditions of use, on battery lifecycle, weather conditions and device usage

Your IQOS 3 MULTI device is designed to work in a wide range of temperatures, but tobacco sticks taste best when you use the device between 0 °C and 50 °C. 

•    One vibration means your IQOS 3 MULTI is  starting to heat up (after you’ve pressed the Holder button to start).
•    Two vibrations mean it’s ready to use.
•    Two more vibrations mean your experience is almost over (it’ll vibrate 30 seconds before the end)  

Press and hold the button on your IQOS 3 MULTI for 10 seconds and then release it. The lights will fade in and out to confirm the reset. 

It takes approximately 75 minutes to fully charge your IQOS 3 MULTI from an electrical outlet, using the IQOS AC Power Adaptor and USB cable.

You can easily check the charge level by following these simple steps: 

1. Press IQOS 3 Multi Button for 1 second 
2. The Battery Status lights will turn on and indicate the level of charge