title: Unable to install rabbitmq due to incorrect versions of erlang dependencies
body: <p>I have <code>erlang 21.3</code> installed:</p>
  
  <pre><code>$ erl -eval 'erlang:display(erlang:system_info(otp_release)), halt().'  -noshell
  "21"
  </code></pre>
  
  <p>But the <code>rabbitmq</code> installer does not think so:</p>
  
  <pre><code>sudo apt-get install -y rabbitmq-server
  Reading package lists... Done
  Building dependency tree
  Reading state information... Done
  Some packages could not be installed. This may mean that you have
  requested an impossible situation or if you are using the unstable
  distribution that some required packages have not yet been created
  or been moved out of Incoming.
  The following information may help to resolve the situation:
  
  The following packages have unmet dependencies:
   rabbitmq-server : Depends: erlang-base (&gt;= 1:21.3) but 1:20.2.2+dfsg-1ubuntu2 is to be installed or
                              erlang-base-hipe (&gt;= 1:21.3) but it is not going to be installed or
                              esl-erlang (&gt;= 1:21.3) but it is not installable
                     Depends: erlang-crypto (&gt;= 1:21.3) but 1:20.2.2+dfsg-1ubuntu2 is to be installed or
                              esl-erlang (&gt;= 1:21.3) but it is not installable
                     Depends: erlang-eldap (&gt;= 1:21.3) but 1:20.2.2+dfsg-1ubuntu2 is to be installed or
                              esl-erlang (&gt;= 1:21.3) but it is not installable
                     Depends: erlang-inets (&gt;= 1:21.3) but 1:20.2.2+dfsg-1ubuntu2 is to be installed or
                              esl-erlang (&gt;= 1:21.3) but it is not installable
                     Depends: erlang-mnesia (&gt;= 1:21.3) but 1:20.2.2+dfsg-1ubuntu2 is to be installed or
                              esl-erlang (&gt;= 1:21.3) but it is not installable
                     Depends: erlang-os-mon (&gt;= 1:21.3) but 1:20.2.2+dfsg-1ubuntu2 is to be installed or
                              esl-erlang (&gt;= 1:21.3) but it is not installable
                     Depends: erlang-parsetools (&gt;= 1:21.3) but 1:20.2.2+dfsg-1ubuntu2 is to be installed or
                              esl-erlang (&gt;= 1:21.3) but it is not installable
                     Depends: erlang-public-key (&gt;= 1:21.3) but 1:20.2.2+dfsg-1ubuntu2 is to be installed or
                              esl-erlang (&gt;= 1:21.3) but it is not installable
                     Depends: erlang-runtime-tools (&gt;= 1:21.3) but 1:20.2.2+dfsg-1ubuntu2 is to be installed or
                              esl-erlang (&gt;= 1:21.3) but it is not installable
                     Depends: erlang-ssl (&gt;= 1:21.3) but 1:20.2.2+dfsg-1ubuntu2 is to be installed or
                              esl-erlang (&gt;= 1:21.3) but it is not installable
                     Depends: erlang-syntax-tools (&gt;= 1:21.3) but 1:20.2.2+dfsg-1ubuntu2 is to be installed or
                              esl-erlang (&gt;= 1:21.3) but it is not installable
                     Depends: erlang-tools (&gt;= 1:21.3) but 1:20.2.2+dfsg-1ubuntu2 is to be installed or
                              esl-erlang (&gt;= 1:21.3) but it is not installable
                     Depends: erlang-xmerl (&gt;= 1:21.3) but 1:20.2.2+dfsg-1ubuntu2 is to be installed or
                              esl-erlang (&gt;= 1:21.3) but it is not installable
  E: Unable to correct problems, you have held broken packages.
  </code></pre>
  
  <p>Note: the following question is similar - but for <code>RedHat</code> and the <code>yum install</code> instructions are not directly applicable for <code>apt-get</code>  <a href="https://stackoverflow.com/questions/49562295/installing-rabbitmq-on-red-hat-wrong-erlang-version">Installing RabbitMQ on Red Hat - wrong Erlang version</a></p>
  
  <p>What needs to be done to fix this installation process? I am on <code>ubuntu 18.0.4</code>.</p>