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blog/2019/fixmasterkeyasregularkey-enabled.md

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+# fixMasterKeyAsRegularKey is Now Available
+
+[As previously announced](https://xrpl.org/blog/2019/fixmasterkeyasregularkey-expected.html), the fixMasterKeyAsRegularKey amendment [became enabled on the XRP Ledger](https://xrpcharts.ripple.com/#/transactions/61096F8B5AFDD8F5BAF7FC7221BA4D1849C4E21B1BA79733E44B12FC8DA6EA20) on 2019-10-02.
+
+## Action Required
+
+- If you operate a `rippled` server, you should upgrade to version 1.3.1 (or higher) immediately.
+
+For instructions on upgrading `rippled` on supported platforms, see [Install `rippled`](https://xrpl.org/install-rippled.html).
+
+
+## Impact of Not Upgrading
+
+If you operate a `rippled` server on a version older than 1.3.1, then your server is now amendment blocked, meaning that your server:
+
+* Cannot determine the validity of a ledger
+* Cannot submit or process transactions
+* Does not participate in the consensus process
+* Does not vote on future amendments
+* Could rely on potentially invalid data
+
+## fixMasterKeyAsRegularKey Summary
+
+Fixes a bug where accounts can set their regular key pair to match their master key pair, but cannot send transactions signed by the key if the master key is disabled.
+
+Without this fix, a user can unintentionally "black hole" their account by setting the regular key to match the master key, then disabling the master key. The network rejects transactions signed with the both-master-and-regular key pair because the code interprets them as being signed with the disabled master key before it recognizes that they are signed by the currently-enabled regular key.
+
+With this amendment enabled, a SetRegularKey transaction cannot set the regular key to match the master key; such a transaction results in the transaction code `temBAD_REGKEY`. Additionally, this amendment changes the signature verification code so that accounts which _already_ have their regular key set to match their master key can send transactions successfully using the key pair.
+
+## Learn, ask questions, and discuss
+Related documentation is available in the [XRP Ledger Dev Portal](https://xrpl.org/), including detailed example API calls and web tools for API testing.
+
+Other resources:
+
+* [The XRP Ledger Dev Blog](https://xrpl.org/blog/)
+* Ripple Technical Services: <support@ripple.com>
+* [XRP Chat Forum](http://www.xrpchat.com/)