2 fix grammatical and spelling errors
source | link

The problem with your $item_info$item_info is that the variablesvariable is not initialized before your try to append to it. $item_info .= 'String content'; is the exacteexact same thing as $item_info = $item_info . 'String content';, so all you need is to check wheterwhether or not this variable existexists:

if (!isset($item_info)) { 
    $item_info = '';
}
$item_info .= '<div class="rustik_updated"><div class="mc_embed_signup_admin">
    <form action="http://doublerainbowx.us6.list-manage2.com/subscribe/post?u=eac2b83a92633c39dae8a663b&amp;id=334c60b856" method="post" id="mc-embedded-subscribe-form" name="mc-embedded-subscribe-form" class="validate" target="_blank" novalidate>
        <label for="mce-EMAIL">Get e-mails about important updates and helpful tips on how to run your store by joining the Rustik newsletter.</label>
        <input type="email" value="" name="EMAIL" class="email" id="mce-EMAIL" placeholder="email address" required>
        <!-- real people should not fill this in and expect good things - do not remove this or risk form bot signups-->
        <div style="position: absolute; left: -5000px;"><input type="text" name="b_eac2b83a92633c39dae8a663b_334c60b856" value=""></div>
        <input type="submit" value="Subscribe" name="subscribe" id="mc-embedded-subscribe" class="button">
        <span><a href="?rustik_updates_nag_ignore=0">Hide Notice</a></span>
    </form>

    </div></div>';

Sometime developerSometimes developers sell themethemes/pluginplugins without testing them with warning onwarnings ON, that's why you have this error.

The problem with your $item_info is that the variables is not initialized before your try to append to it. $item_info .= 'String content'; is the exacte same thing as $item_info = $item_info . 'String content'; so all you need is to check wheter or not this variable exist

if (!isset($item_info)) { 
    $item_info = '';
}
$item_info .= '<div class="rustik_updated"><div class="mc_embed_signup_admin">
    <form action="http://doublerainbowx.us6.list-manage2.com/subscribe/post?u=eac2b83a92633c39dae8a663b&amp;id=334c60b856" method="post" id="mc-embedded-subscribe-form" name="mc-embedded-subscribe-form" class="validate" target="_blank" novalidate>
        <label for="mce-EMAIL">Get e-mails about important updates and helpful tips on how to run your store by joining the Rustik newsletter.</label>
        <input type="email" value="" name="EMAIL" class="email" id="mce-EMAIL" placeholder="email address" required>
        <!-- real people should not fill this in and expect good things - do not remove this or risk form bot signups-->
        <div style="position: absolute; left: -5000px;"><input type="text" name="b_eac2b83a92633c39dae8a663b_334c60b856" value=""></div>
        <input type="submit" value="Subscribe" name="subscribe" id="mc-embedded-subscribe" class="button">
        <span><a href="?rustik_updates_nag_ignore=0">Hide Notice</a></span>
    </form>

    </div></div>';

Sometime developer sell theme/plugin without testing them with warning on, that's why you have this error.

The problem with your $item_info is that the variable is not initialized before your try to append to it. $item_info .= 'String content'; is the exact same thing as $item_info = $item_info . 'String content';, so all you need is to check whether or not this variable exists:

if (!isset($item_info)) { 
    $item_info = '';
}
$item_info .= '<div class="rustik_updated"><div class="mc_embed_signup_admin">
    <form action="http://doublerainbowx.us6.list-manage2.com/subscribe/post?u=eac2b83a92633c39dae8a663b&amp;id=334c60b856" method="post" id="mc-embedded-subscribe-form" name="mc-embedded-subscribe-form" class="validate" target="_blank" novalidate>
        <label for="mce-EMAIL">Get e-mails about important updates and helpful tips on how to run your store by joining the Rustik newsletter.</label>
        <input type="email" value="" name="EMAIL" class="email" id="mce-EMAIL" placeholder="email address" required>
        <!-- real people should not fill this in and expect good things - do not remove this or risk form bot signups-->
        <div style="position: absolute; left: -5000px;"><input type="text" name="b_eac2b83a92633c39dae8a663b_334c60b856" value=""></div>
        <input type="submit" value="Subscribe" name="subscribe" id="mc-embedded-subscribe" class="button">
        <span><a href="?rustik_updates_nag_ignore=0">Hide Notice</a></span>
    </form>

    </div></div>';

Sometimes developers sell themes/plugins without testing them with warnings ON, that's why you have this error.

1
source | link

The problem with your $item_info is that the variables is not initialized before your try to append to it. $item_info .= 'String content'; is the exacte same thing as $item_info = $item_info . 'String content'; so all you need is to check wheter or not this variable exist

if (!isset($item_info)) { 
    $item_info = '';
}
$item_info .= '<div class="rustik_updated"><div class="mc_embed_signup_admin">
    <form action="http://doublerainbowx.us6.list-manage2.com/subscribe/post?u=eac2b83a92633c39dae8a663b&amp;id=334c60b856" method="post" id="mc-embedded-subscribe-form" name="mc-embedded-subscribe-form" class="validate" target="_blank" novalidate>
        <label for="mce-EMAIL">Get e-mails about important updates and helpful tips on how to run your store by joining the Rustik newsletter.</label>
        <input type="email" value="" name="EMAIL" class="email" id="mce-EMAIL" placeholder="email address" required>
        <!-- real people should not fill this in and expect good things - do not remove this or risk form bot signups-->
        <div style="position: absolute; left: -5000px;"><input type="text" name="b_eac2b83a92633c39dae8a663b_334c60b856" value=""></div>
        <input type="submit" value="Subscribe" name="subscribe" id="mc-embedded-subscribe" class="button">
        <span><a href="?rustik_updates_nag_ignore=0">Hide Notice</a></span>
    </form>

    </div></div>';

Sometime developer sell theme/plugin without testing them with warning on, that's why you have this error.