Bought a Digi SIM to test out the recently upgraded sites, let's say to 4T6S or AAU. Most sites are having problem from running on 4CA, resulting into slower 4G+ speed after the upgrade.

The worst scenario is most of the upgraded sites started to broadcast 2G on 900MHz as well, due to Digi limited 900MHz spectrum, the precious LTE Band 8 was squeezed from 5MHz to 3MHz. Due to 3GPP standard, 3MHz bandwidth LTE is not allow for carrier aggregation resulting into awful single digit slow speed if your phone accidentally dropped to Band 8....

Besides that, compared to Celcom and Maxis, Digi has a way higher tendency on connecting Band 8 as the primary LTE carrier. Honestly, this is a terrible decision. Customers could not enjoy the best available network.

Last but not least, most of the uncombined upgraded sites stays on 2CA even on high band, it either do B1+B3, B3+B7 or B1+B7, but could not do B1+B3+B7. Terrible experience if u are an existing Digi customer experienced the network before upgrade and after upgrade

Android users on Digi, force yr phone on 4G not 5G, install CellMapper. If your phone shows  MY CELCOM instead of Digi on the top. It means the network is integrated.
For Celcom users, force yr phone to 4G as well, install CellMapper or any cell tracking tools. If the TAC number shows 5 digits, very likely the network has been merged.

NetMonster for Android will give u a hint as well, Celcom's EARFCN are 1650, 3150, 375, and 3600. Digi's EARFCN 1850, 3350, 524, and 3524. If you are from telco A but see telco B's EARFCN as one of the carrier for 4G+ CA in NetMonster, means the network had been merged.

Alternative way for iPhone and non CelcomDigi customers are going through CellMapper map and depending on crowd source data.
Pick Celcom, if u see 5 digits eNodeB number instead of 6 digits in north and central Malaysia, means the network had been merged. South and east coast is harder to identify, same just pick Celcom in CellMapper map, and see if most recently mapped cells have a 5 digits Region code, if so that means merged already

Band 1

Band 3

Band 7

Band 8