New models of TellStick will no longer support 433MHz as it is an old technology that is insecure and one-way communication. You will never know if a plug is turned on or not until you physically inspect it, for example. This is not the smart home we envisioned in your future. That is why Telldus has turned towards Bluetooth mesh, Zigbee and Matter as alternatives to 433MHz. All these allow us to offer devices at similar cost to the 433MHz ones yet with better security and reliability. With this change, we are also able to bring a plethora of smart devices to the portfolio with respect to the design, cost and size.
On the other hand, some major components on the TellStick Net/ZNet lite v2 are either no longer available or have become extremely expensive. Offering a new TellStick that would continue to work with the current 433MHz devices is no longer an option to us, even if we want to.