README.md in africastalking-ruby-2.1.7 vs README.md in africastalking-ruby-2.1.8

@@ -66,9 +66,11 @@
     - `recipients`: Contains an hash of arrays containing the following keys
         - `phoneNumber`: Recipient of airtime `REQUIRED`
         - `currency`:3-digit ISO format currency code . `REQUIRED`
         - `amount`: Amount sent `>= 10 && <= 10K` with currency e.g `KES 100` `REQUIRED`
 
+ - `maxNumRetry`: This allows you to specify the maximum number of retries in case of failed airtime deliveries due to various reasons such as telco unavailability. The default retry period is 8 hours and retries occur every 60seconds. For example, setting `maxNumRetry=4` means the transaction will be retried every 60seconds for the next 4 hours.`OPTIONAL`.
+  
 ### Sms
 
 ```ruby
 sms = @AT.sms
 ```