For M1 Maxx mobile plans, there are 2 types:
(1) DOES NOT auto renew (non-recurring).
(2) Will auto renew (recurring).
When M1 Maxx first started, there was only type (1) non-recurring mobile plans;
- Type (2) auto renew (recurring) mobile plans for M1 Maxx -- was only added later.
For type (1) non-recurring mobile plans, the list can be found at this link:
https://maxx.sg/add-on
The above list of type (1) M1 Maxx non-recurring mobile plans is not fixed/permanent.
(i.e. the quota/price for each mobile plan can be updated/changed from time-to-time & new mobile plans can also be added.)
When M1 Maxx first started, type (1) non-recurring mobile plans were only available at retailers (shops).
But later you can also buy type (1) M1 Maxx mobile plans from online platforms like
Shopee.sg (often at discounted prices).
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(If I'm not wrong) My understanding is as follows:
If you're currently having on a type (2) auto renew (recurring) M1 Maxx plan -- and you make a plan change without stopping/terminating auto renew, the new plan will (logically) replace the current plan -- because M1 Maxx system may not support/allow you to subscribe to more than 1 recurring/auto renew mobile plan running concurrently.
But this restriction of having only 1 x type (2) auto renew (recurring) mobile plan at any point in time -- DOES NOT SEEMS to apply to type (1) non-recurring M1 Maxx mobile plans.
Last year (2022),
I bought a second type (1) M1 Maxx plan on Shopee.sg -- BEFORE my current type (1) M1 Maxx plan expire.
(The reason why I do so -- is because quota on my current M1 Maxx plan was running low + I wanted to test out buying
M1 Maxx plan at discounted prices on Shopee.sg)
After buying the second type (1) M1 Maxx mobile plan, both current & newly bought mobile plans are shown in the M1 Maxx app -- with overlapping validity periods;
- so during the overlapping period -- both type (1) M1 Maxx mobile plans are active.
Unless things have changed, but based on the above,
- it may also be possible to add-on/buy another type (1) non-recurring mobile plan -- while concurrently having a type (2) recurring/auto renew M1 Maxx mobile plan.
I can't confirm this as I don't intend to use any recurring/auto renew mobile plan on my M1 Maxx line -- but I did have 2 x type (1) non-recurring M1 Maxx mobile plans running with overlapping validity once in 2022 (as stated above).
This is the reason why many people have stated that M1 Maxx is a hybrid postpaid/prepaid combo serivce -- although M1 Maxx itself is classified as postpaid.