It seems that they're thinking of ceasing off 3G first instead.
2G network are still being used today, especially from Machine-to-Machine (M2M) and Internet-of-Things (IoT), mainly from commercial business and uses... Not for average daily consumers like us, except those elderly that uses 2G phone.
Although yes, 2G is "outdated" but somehow it still tends to generate some revenue for telcos.
If those devices were to be upgraded to support 4G, it's gonna involve some great costs to owners to buy and upgrade.
After all, those machines/devices uses less than around 50MB per month, where 2G network (either via GPRS or EDGE) are already sufficient to satisfy their needs, hence they don't necessarily need a high speed 4G network for their applications.
Either way, shutting down 3G might be making sense. We don't see many new 3G-only phones on market nowadays... Even the market's cheapest and lousiest phone are likely to support 4G already (whether it supports VoLTE or not, then it's different story

)
For the elderly people that is not tech savvy ones, they are either still on their 2G feature phones, OR already on 4G-enabled smartphones.
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All Malaysian telcos already supports VoLTE, except...:
Celcom VoLTE is available to all Celcom Mobile Postpaid plan customers using iPhone 7 and above only.
Maxis, don't have VoLTE yet at all.
By the time when 3G has fully shutdown, and if you use a 4G phone that doesn't support VoLTE, then it would fallback to 2G network during calls.
Malaysia government really doing upside way. Other countries shutdown 2G, maintain 3G bt our country shutdown 3G and maintain 2G?
If you say 2G is still using the machine-to-machine (M2M) for those using commercial and business purposes. I think can't make sense. Compare from nearby country Singapore, they already shutdown 2G bt maintain 3G. So is means that they don't use so called M2M and IoT for commercial and business purposes anymore?