Hi - according to a current Telstra offer, if you order a Telstra Smart Booster Gen 2 and your current modem is not compatible, you qualify for a $0 modem upgrade and Telstra will send you a Telstra Smart Modem Gen 2 to replace your modem. The Boosters are compatible with Telstra Gen 1.1 and Gen 2 modems only, so I assume you qualify - suggest you confirm with Telstra first.
One forum post did this and received the Booster but is still waiting for the Gen 2 modem to arrive, so not sure if Telstra has current stock issues or lack of good internal communication synchronisation for logistical processes.
https://crowdsupport.telstra.com.au/t5/home-broadband/wifi-booster/td-p/897994
@David701 - maybe keep try phoning Telstra during Off Peak times - the Booster works with the Technicolor DJA0230 (Gen 1.1) and the DJA0231 (Gen 2) modems only, so if your Technicolor is an earlier version, you qualify. I assume your current modem is known to Telstra per your account records and it may have had to be reconfirmed when you ordered the Booster.
Hello