Migrate paragraph fields I have migrated Drupal 7 website to Drupal 8 version using the core migrate_drupal_ui module successfully but the paragraph module was broken upgrade path which results in final that the paragraph bundles not migrated and I have created in the new site like the old.

Now I need to migrate content for the paragraph fields only and update the nodes, I did some research and found possible solutions as follows:

1- Custom migrate plugin But I don't know how to edit existing.

2- custom script to read the nodes from other site by creating feeds and update.

//$nid get from feeds.
$entity = entity_load('node', $nid);

$entity-&gt;set('field_audit', 
['field_number' =&gt; [0 =&gt; ['value' =&gt; 4]], 
'field_regular_materials' =&gt; [0 =&gt; ['value' =&gt; '44']], 
'field_verification' =&gt; [0 =&gt; ['value' =&gt; '444']]], FALSE); 

$entity-&gt;save();



  That code gives error Fatal error: Maximum function nesting level of '256' reached, aborting!


what is the best practice to achieve.
I would approach this differently. Using PHPMyAdmin or a Database viewer program, I would look at the Database for the paragraph fields table. Then just export table from D7 as a CSV file. 

In D8, fill out 1 node paragraph values, just so you get the table structure, and export table as CSV.

Then with excel (or Libre office Calc) copy and paste values from one CSV to another. 

Import CSV to D8 Database. 

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