In v11 I got the error,

"""ValueError: View inheritance may not use attribute 'string' as a selector."""

  <xpath expr="//page[@name='sales']" position="attributes">

    <attribute name="string">Purchase</attribute> 

  </xpath>

So, I used the page string position to work with it 

<xpath expr="//page[1]" position="attributes">

    <attribute name="string">Purchase</attribute> 

</xpath>

<record id="module.action_name" model="ir.actions.act_window">

      <field name="name">scheduler</field>

</record>

<page string="Meeting Details" position="attributes">

     <attribute name="string">Scheduler</string>

</page>

 1- <record model="ir.ui.menu" id="id_of_the_menu">

         <field name="name">scheduler</field>          

    </record>

2- inherit the form and modify the form string to Scheduler Details