title: iOS auto renewing subscription (sandbox)
body: <p>I am currently testing my code for auto renewing subscriptions. In most cases it works as expected. But, from times to times, I see unexpected results. </p>
  
  <p>I buy a new subscription, I get a receipt (transaction_id = 1000000075229775).
  Just after receiving this receipt (before the expiration date is reached), I send this receipt to sandbox.itunes.apple.com and it returns a new receipt with a different transaction ID (latest_receipt_info with transaction_id = 1000000075229779).
  I was not expecting to get this new receipt (with a different transaction ID) before the first expiration date is reached.
  Here is an extract of both receipts. Note that the expiration dates are very close (less than one second difference).</p>
  
  <p>Could you please help me understand what is happening ?</p>
  
  <p>Thanks.</p>
  
  <pre><code>["receipt"]=&gt;object(stdClass)#14 (19) {
      ["original_purchase_date_pst"]=&gt;string(39) "2012-12-03 08:20:49 America/Los_Angeles"
      ["unique_identifier"]=&gt;string(40) "af430ef98d6bdbbf92ed34e4addec2e834bc25d6"
      ["original_transaction_id"]=&gt;string(16) "1000000059708880"
      ["expires_date"]=&gt;string(13) "1369421691100"
      ["transaction_id"]=&gt;string(16) "1000000075229775"
      ["quantity"]=&gt;string(1) "1"
      ["expires_date_formatted"]=&gt;string(27) "2013-05-24 18:54:51 Etc/GMT"
      ["purchase_date"]=&gt;string(27) "2013-05-24 18:49:51 Etc/GMT"
      ["purchase_date_ms"]=&gt;string(13) "1369421391100"
      ["original_purchase_date"]=&gt;string(27) "2012-12-03 16:20:49 Etc/GMT"
      ["original_purchase_date_ms"]=&gt;string(13) "1354551649000"
      ...
  }
  ["latest_receipt_info"]=&gt;object(stdClass)#12 (19) {
      ["original_purchase_date_pst"]=&gt;string(39) "2012-12-03 08:20:49 America/Los_Angeles"
      ["unique_identifier"]=&gt;string(40) "345fade172e62c805d0d354edda97575fc9b9d50"
      ["original_transaction_id"]=&gt;string(16) "1000000059708880"
      ["expires_date"]=&gt;string(13) "1369421691000"
      ["transaction_id"]=&gt;string(16) "1000000075229779"
      ["quantity"]=&gt;string(1) "1"
      ["expires_date_formatted"]=&gt;string(27) "2013-05-24 18:54:51 Etc/GMT"
      ["purchase_date"]=&gt;string(27) "2013-05-24 18:49:51 Etc/GMT"
      ["purchase_date_ms"]=&gt;string(13) "1369421391000"
      ["original_purchase_date"]=&gt;string(27) "2012-12-03 16:20:49 Etc/GMT"
      ["original_purchase_date_ms"]=&gt;string(13) "1354551649000"
      ...
  }
  ["status"]=&gt;int(0)
  </code></pre>