BFI Extended Signature - Search String Based

Content Authoring SUA Signatures
1

Does anybody have an example of a BFI signature that reads the content of a file to determine if an specific software version is installed?
I’ve tried different options but none of them have worked.
This is the last attempt:

<MultipleInstance>
  <Iterator name="file_list" export="false">
    <FindFilePathEx name="Versions.txt" />
  </Iterator>
  <Instance>
    <Variable name="file_read" export="false">
      <ReadFile path="$(file_list)Versions.txt" />
    </Variable>
    <Variable name="IS_INSTALLED">
      <Compare type="string" relation="ne">
        <VectorToScalar>
          <Vector filter="*Version: 1.6.1*">
          <ValueOf value="$(file_read)" />
          </Vector>
        </VectorToScalar>
        <ValueOf value="" />
      </Compare>
    </Variable>
    <Condition withVariable="IS_INSTALLED">
      <Action onValue="false" do="SKIP" />
    </Condition>
  </Instance>
</MultipleInstance>

I’m running the ‘wscansw.exe’ command on-demand to test it, but I got 0 matches.
The file Versions.txt exists and contains the following:

Implementation-Title: Daemon
Specification-Version: 1.6.1
2

Can you try below signature?

<MultipleInstance>
	<Iterator export="true" name="INSTALL_PATH">
		<FindFilePathEx name="MYFILE.txt"/>
	</Iterator>
	<Instance>
		<Variable export="false" name="file_read">
			<ReadFile path="$(INSTALL_PATH)MYFILE.txt"/>
		</Variable>
		<Variable name="IS_INSTALLED">
			<Contains inputString="$(file_read)" position="contains" searchedString="MYAPP_version=1.3"/>
		</Variable>
		<Condition withVariable="IS_INSTALLED">
			<Action do="SKIP" onValue="false"/>
		</Condition>
	</Instance>
</MultipleInstance>

Check below link since it contains a post to debug the signature issue