On 22.01.2020, I got a mail with 'Top Warnings: data-vocabulary.org schema deprecated' from Google Search Console Team for my Blogger sites.

I hope maximum Blogger users got the same notification.
Fix Data-vocabulary.org Schema Deprecated Error

This warning is also appeared in your Google Search Console (Former Webmaster) accounts as below -
New Breadcrumbs issue detected for site!
data-vocabulary.org schema is deprecated and not supported by Google anymore. Please migrate to using schema.org types.
That means, data-vocabulary.org schema feature is closed and we have to migrate to Schema.org.

It has been announced in official blog of Official Google Webmaster.

The similar markup for Breadcrumbs List in Schema.org is  BreadcrumbList.

Okay! We are now going to update the Breadcrumbs with Schema.org Microdata in our Blogger Template/Theme.

This tutorial is advanced. If you don't know customizing Blogger Template with code, then it will be difficult to solve this issue. Because different Blogger Theme Developers place the breadcrumb code in different way. So you need to contact your Developer or You can hire me to solve this error!.

4 Steps to Fix data-vocabulary.org Schema Deprecated Error in Blogger

Important: Backup your Blogger Theme XML File before editing on it. 
  1. Open your Blogger Theme XML File in your Favorite Editor. 
  2. Find your Breadcrumb code segment. You can find this segment by search <b:includable id='breadcrumb' var='posts'> . After this line, just paste the following code.
    <b:if cond='data:blog.pageType == "item"'>
    <div class="breadcrumb-outer">
    <div itemscope='' itemtype="http://schema.org/BreadcrumbList">
    <b:if cond='data:post.labels'>
    <span itemprop="itemListElement" itemscope='' itemtype="http://schema.org/ListItem"><a expr:href='data:blog.homepageUrl' itemprop="item"><span style='padding-left:8px;' itemprop="name">Home</span></a><meta itemprop="position" content="1" /></span>»
    <b:loop values='data:post.labels' var='label' index='i'>
    <b:if cond='data:i == 0'>
    <span itemprop="itemListElement" itemscope='' itemtype="http://schema.org/ListItem"><a expr:href='data:label.url + "?&amp;max-results=7"' itemprop="item"><span itemprop="name"> <data:label.name/></span></a><meta itemprop="position" expr:content='data:i + 2' /></span><b:if cond='data:label.isLast != "true"'/>»
    </b:if> <!--CONDITION-->
    <span class="breadcrumb-title" expr:title='data:post.title'>
  3. Don't forget to remove the older Breadcrumb code.
  4. Update the Theme in your website. 
  5. Check the Post URL in Structured Data Testing Tool whether it is working or not.  
If it isn't work then put your comment below, I will try to help.