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The “Referral Program” section of Admin Settings page has option to turn the feature on and off as well as the amounts of rewarded credit for the promoter and newcomer user:
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Configuration specific to pre-payment billing scheme
For a pre-payment billing accounts, a threshold parameter Receiver top up requirement can be used to set a minimum amount of top-ups that first needs to be bought by the user to get extra credit for using a referral code.
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