diff --git a/blocks/api/parser.js b/blocks/api/parser.js
index 94a1dfe92f4f03..82add30a463e8f 100644
--- a/blocks/api/parser.js
+++ b/blocks/api/parser.js
@@ -2,7 +2,7 @@
  * External dependencies
  */
 import { parse as hpqParse } from 'hpq';
-import { mapValues, find, omit } from 'lodash';
+import { mapValues, omit } from 'lodash';
 
 /**
  * Internal dependencies
@@ -129,6 +129,32 @@ export function getBlockAttributes( blockType, innerHTML, attributes ) {
 	return blockAttributes;
 }
 
+/**
+ * Attempt to parse the innerHTML using using a supplied `deprecated` definition.
+ *
+ * @param  {?Object} blockType  Block type
+ * @param  {string}  innerHTML  Raw block content
+ * @param  {?Object} attributes Known block attributes (from delimiters)
+ * @return {Object}             Block attributes
+ */
+export function getAttributesFromDeprecatedVersion( blockType, innerHTML, attributes ) {
+	if ( ! blockType.deprecated ) {
+		return;
+	}
+
+	for ( let i = 0; i < blockType.deprecated.length; i++ ) {
+		const deprecatedBlockType = {
+			...omit( blockType, [ 'attributes', 'save', 'supports' ] ), // Parsing/Serialization properties
+			...blockType.deprecated[ i ],
+		};
+		const deprecatedBlockAttributes = getBlockAttributes( deprecatedBlockType, innerHTML, attributes );
+		const isValid = isValidBlock( innerHTML, deprecatedBlockType, deprecatedBlockAttributes );
+		if ( isValid ) {
+			return deprecatedBlockAttributes;
+		}
+	}
+}
+
 /**
  * Creates a block with fallback to the unknown type handler.
  *
@@ -181,23 +207,14 @@ export function createBlockWithFallback( name, innerHTML, attributes ) {
 		// as invalid, or future serialization attempt results in an error
 		block.originalContent = innerHTML;
 
-		// When a block is invalid, attempt to validate again using a supplied `deprecated` definition.
+		// When a block is invalid, attempt to parse it using a supplied `deprecated` definition.
 		// This allows blocks to modify their attribute and markup structure without invalidating
 		// content written in previous formats.
-		if ( ! block.isValid && blockType.deprecated ) {
-			let attributesParsedWithDeprecatedVersion;
-			const hasValidOlderVersion = find( blockType.deprecated, ( oldBlockType ) => {
-				const deprecatedBlockType = {
-					...omit( blockType, [ 'attributes', 'save', 'supports' ] ), // Parsing/Serialization properties
-					...oldBlockType,
-				};
-				const deprecatedBlockAttributes = getBlockAttributes( deprecatedBlockType, innerHTML, attributes );
-				const isValid = isValidBlock( innerHTML, deprecatedBlockType, deprecatedBlockAttributes );
-				attributesParsedWithDeprecatedVersion = isValid ? deprecatedBlockAttributes : undefined;
-				return isValid;
-			} );
-
-			if ( hasValidOlderVersion ) {
+		if ( ! block.isValid ) {
+			const attributesParsedWithDeprecatedVersion = getAttributesFromDeprecatedVersion(
+				blockType, innerHTML, attributes
+			);
+			if ( attributesParsedWithDeprecatedVersion ) {
 				block.isValid = true;
 				block.attributes = attributesParsedWithDeprecatedVersion;
 			}
diff --git a/blocks/api/test/parser.js b/blocks/api/test/parser.js
index 8ef32c002891d5..8c2205b18f14f4 100644
--- a/blocks/api/test/parser.js
+++ b/blocks/api/test/parser.js
@@ -6,6 +6,7 @@ import {
 	getBlockAttributes,
 	asType,
 	createBlockWithFallback,
+	getAttributesFromDeprecatedVersion,
 	default as parse,
 } from '../parser';
 import {
@@ -15,6 +16,15 @@ import {
 	setUnknownTypeHandlerName,
 } from '../registration';
 
+const expectFailingBlockValidation = () => {
+	/* eslint-disable no-console */
+	expect( console.error ).toHaveBeenCalled();
+	expect( console.warn ).toHaveBeenCalled();
+	console.warn.mockClear();
+	console.error.mockClear();
+	/* eslint-enable no-console */
+};
+
 describe( 'block parser', () => {
 	const defaultBlockSettings = {
 		attributes: {
@@ -164,6 +174,62 @@ describe( 'block parser', () => {
 		} );
 	} );
 
+	describe( 'getAttributesFromDeprecatedVersion', () => {
+		it( 'should return undefined if the block has no deprecated versions', () => {
+			const attributes = getAttributesFromDeprecatedVersion(
+				defaultBlockSettings,
+				'<span class="wp-block-test-block">Bananas</span>',
+				{},
+			);
+			expect( attributes ).toBeUndefined();
+		} );
+
+		it( 'should return undefined if no valid deprecated version found', () => {
+			const attributes = getAttributesFromDeprecatedVersion(
+				{
+					name: 'core/test-block',
+					...defaultBlockSettings,
+					deprecated: [
+						{
+							save() {
+								return 'nothing';
+							},
+						},
+					],
+				},
+				'<span class="wp-block-test-block">Bananas</span>',
+				{},
+			);
+			expect( attributes ).toBeUndefined();
+			expectFailingBlockValidation();
+		} );
+
+		it( 'should return the attributes parsed by the deprecated version', () => {
+			const attributes = getAttributesFromDeprecatedVersion(
+				{
+					name: 'core/test-block',
+					...defaultBlockSettings,
+					save: ( props ) => <div>{ props.attributes.fruit }</div>,
+					deprecated: [
+						{
+							attributes: {
+								fruit: {
+									type: 'string',
+									source: 'text',
+									selector: 'span',
+								},
+							},
+							save: ( props ) => <span>{ props.attributes.fruit }</span>,
+						},
+					],
+				},
+				'<span class="wp-block-test-block">Bananas</span>',
+				{},
+			);
+			expect( attributes ).toEqual( { fruit: 'Bananas' } );
+		} );
+	} );
+
 	describe( 'createBlockWithFallback', () => {
 		it( 'should create the requested block if it exists', () => {
 			registerBlockType( 'core/test-block', defaultBlockSettings );
@@ -245,12 +311,7 @@ describe( 'block parser', () => {
 			expect( block.name ).toEqual( 'core/test-block' );
 			expect( block.attributes ).toEqual( { fruit: 'Bananas' } );
 			expect( block.isValid ).toBe( true );
-			/* eslint-disable no-console */
-			expect( console.error ).toHaveBeenCalled();
-			expect( console.warn ).toHaveBeenCalled();
-			console.warn.mockClear();
-			console.error.mockClear();
-			/* eslint-enable no-console */
+			expectFailingBlockValidation();
 		} );
 	} );