allowed_versions={v1.0,v1.1,v1.5,v2.3}
read -r -p 'Enter a version: ' version_inputted
if [[ "${version_inputted}" == "${allowed_versions}" ]]
then
  echo 'That version is allowed.'
else
  echo 'That version is NOT allowed.'
fi

Enter a version: v1.0
That version is allowed.

Enter a version: v9.6
That version is NOT allowed.

Enter a version: v1.5
That version is allowed.

Enter a version: asdflj';~!@ #$%^&*)_+=-<>,.?/~`|}{][:"(
That version is NOT allowed.