social/mail_digest/data/ir_cron.xml

<?xml version="1.0" encoding="utf-8"?>
<odoo>
    <data noupdate="1">
        <record forcecreate="True" id="ir_cron_mail_digest_daily_action" model="ir.cron">
            <field name="name">Digest mail process - daily</field>
            <field name="user_id" ref="base.user_root"/>
            <field name="interval_number">1</field>
            <field name="interval_type">days</field>
            <field name="numbercall">-1</field>
            <field eval="False" name="doall"/>
            <field eval="'mail.digest'" name="model"/>
            <field eval="'process'" name="function"/>
            <field eval="'()'" name="args"/>
        </record>
        <record forcecreate="True" id="ir_cron_mail_digest_weekly_action" model="ir.cron">
            <field name="name">Digest mail process - weekly</field>
            <field name="user_id" ref="base.user_root"/>
            <field name="interval_number">1</field>
            <field name="interval_type">weeks</field>
            <field name="numbercall">-1</field>
            <field eval="False" name="doall"/>
            <field eval="'mail.digest'" name="model"/>
            <field eval="'process'" name="function"/>
            <field eval="'(\'weekly\',)'" name="args"/>
        </record>
    </data>
</odoo>