diff --git a/CHANGES.rst b/CHANGES.rst
index 7870758b7..fb0f051c8 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -14,6 +14,12 @@
   is still effective and the active memory maps may still require the file
   to stay open in case ``copy_arrays`` is ``False``. [#573]
 
+- Storage of arbitrary precision integers is now provided by
+  ``asdf.IntegerType``.  Reading a file with integer literals that are too
+  large now causes only a warning instead of a validation error. This is to
+  provide backwards compatibility for files that were created with a buggy
+  version of ASDF (see #553 below). [#566]
+
 2.1.1 (unreleased)
 ------------------
 
diff --git a/asdf-standard b/asdf-standard
index 0bc7aa7c6..dfada9046 160000
--- a/asdf-standard
+++ b/asdf-standard
@@ -1 +1 @@
-Subproject commit 0bc7aa7c6b7b2099174f6ac40e2590f366f8b092
+Subproject commit dfada904677a6b7f5e7473977fe9a14c4ecb8277
diff --git a/asdf/__init__.py b/asdf/__init__.py
index 224028fba..4586236be 100644
--- a/asdf/__init__.py
+++ b/asdf/__init__.py
@@ -15,7 +15,7 @@
 
 __all__ = [
     'AsdfFile', 'CustomType', 'AsdfExtension', 'Stream', 'open', 'test',
-    'commands', 'ExternalArrayReference'
+    'commands', 'IntegerType', 'ExternalArrayReference'
 ]
 
 try:
@@ -38,6 +38,7 @@
 from .extension import AsdfExtension
 from .stream import Stream
 from . import commands
+from .tags.core import IntegerType
 from .tags.core.external_reference import ExternalArrayReference
 
 from jsonschema import ValidationError
diff --git a/asdf/asdf.py b/asdf/asdf.py
index 0d75d8e63..f476dc11c 100644
--- a/asdf/asdf.py
+++ b/asdf/asdf.py
@@ -414,13 +414,14 @@ def comments(self):
         """
         return self._comments
 
-    def _validate(self, tree, custom=True):
+    def _validate(self, tree, custom=True, reading=False):
         tagged_tree = yamlutil.custom_tree_to_tagged_tree(
             tree, self)
-        schema.validate(tagged_tree, self)
+        schema.validate(tagged_tree, self, reading=reading)
         # Perform secondary validation pass if requested
         if custom and self._custom_schema:
-            schema.validate(tagged_tree, self, self._custom_schema)
+            schema.validate(tagged_tree, self, self._custom_schema,
+                            reading=reading)
 
     def validate(self):
         """
@@ -651,10 +652,10 @@ def _open_asdf(cls, self, fd, uri=None, mode='r',
 
         tree = reference.find_references(tree, self)
         if not do_not_fill_defaults:
-            schema.fill_defaults(tree, self)
+            schema.fill_defaults(tree, self, reading=True)
 
         try:
-            self._validate(tree)
+            self._validate(tree, reading=True)
         except ValidationError:
             self.close()
             raise
diff --git a/asdf/schema.py b/asdf/schema.py
index d7ac26378..ac68b9a69 100644
--- a/asdf/schema.py
+++ b/asdf/schema.py
@@ -458,21 +458,33 @@ def get_validator(schema={}, ctx=None, validators=None, url_mapping=None,
     return validator
 
 
-def validate_large_literals(instance):
+def validate_large_literals(instance, reading=False):
     """
     Validate that the tree has no large numeric literals.
     """
     # We can count on 52 bits of precision
     for instance in treeutil.iter_tree(instance):
-        if (isinstance(instance, (Integral)) and (
-            instance > ((1 << 51) - 1) or
-            instance < -((1 << 51) - 2))):
+
+        if not isinstance(instance, Integral):
+            continue
+
+        if instance <= ((1 << 51) - 1) and instance >= -((1 << 51) - 2):
+            continue
+
+        if not reading:
             raise ValidationError(
                 "Integer value {0} is too large to safely represent as a "
                 "literal in ASDF".format(instance))
 
+        warnings.warn(
+            "Invalid integer literal value {0} detected while reading file. "
+            "The value has been read safely, but the file should be "
+            "fixed.".format(instance)
+        )
 
-def validate(instance, ctx=None, schema={}, validators=None, *args, **kwargs):
+
+def validate(instance, ctx=None, schema={}, validators=None, reading=False,
+             *args, **kwargs):
     """
     Validate the given instance (which must be a tagged tree) against
     the appropriate schema.  The schema itself is located using the
@@ -495,6 +507,11 @@ def validate(instance, ctx=None, schema={}, validators=None, *args, **kwargs):
     validators : dict, optional
         A dictionary mapping properties to validators to use (instead
         of the built-in ones and ones provided by extension types).
+
+    reading: bool, optional
+        Indicates whether validation is being performed when the file is being
+        read. This is useful to allow for different validation behavior when
+        reading vs writing files.
     """
     if ctx is None:
         from .asdf import AsdfFile
@@ -504,10 +521,10 @@ def validate(instance, ctx=None, schema={}, validators=None, *args, **kwargs):
                               *args, **kwargs)
     validator.validate(instance, _schema=(schema or None))
 
-    validate_large_literals(instance)
+    validate_large_literals(instance, reading=reading)
 
 
-def fill_defaults(instance, ctx):
+def fill_defaults(instance, ctx, reading=False):
     """
     For any default values in the schema, add them to the tree if they
     don't exist.
@@ -518,8 +535,12 @@ def fill_defaults(instance, ctx):
 
     ctx : AsdfFile context
         Used to resolve tags and urls
+
+    reading: bool, optional
+        Indicates whether the ASDF file is being read (in contrast to being
+        written).
     """
-    validate(instance, ctx, validators=FILL_DEFAULTS)
+    validate(instance, ctx, validators=FILL_DEFAULTS, reading=reading)
 
 
 def remove_defaults(instance, ctx):
diff --git a/asdf/tags/core/__init__.py b/asdf/tags/core/__init__.py
index 5233f834e..7e0dadd02 100644
--- a/asdf/tags/core/__init__.py
+++ b/asdf/tags/core/__init__.py
@@ -44,4 +44,5 @@ def to_tree(cls, node, ctx):
 from .constant import ConstantType
 from .ndarray import NDArrayType
 from .complex import ComplexType
+from .integer import IntegerType
 from .external_reference import ExternalArrayReference
diff --git a/asdf/tags/core/integer.py b/asdf/tags/core/integer.py
new file mode 100644
index 000000000..0d1d62972
--- /dev/null
+++ b/asdf/tags/core/integer.py
@@ -0,0 +1,121 @@
+# Licensed under a 3-clause BSD style license - see LICENSE.rst
+# -*- coding: utf-8 -*-
+
+from numbers import Integral
+
+import numpy as np
+
+from ...asdftypes import AsdfType
+from ...yamlutil import custom_tree_to_tagged_tree
+
+
+class IntegerType(AsdfType):
+    """
+    Enables the storage of arbitrarily large integer values
+
+    The ASDF Standard mandates that integer literals in the tree can be no
+    larger than 52 bits. Use of this class enables the storage of arbitrarily
+    large integer values.
+
+    When reading files that contain arbitrarily large integers, the values that
+    are restored in the tree will be raw Python `int` instances.
+
+    Parameters
+    ----------
+
+    value: `numbers.Integral`
+        A Python integral value (e.g. `int` or `numpy.integer`)
+
+    storage_type: `str`, optional
+        Optionally overrides the storage type of the array used to represent
+        the integer value. Valid values are "internal" (the default) and
+        "inline"
+
+    Examples
+    --------
+
+    >>> import asdf
+    >>> import random
+    >>> # Create a large integer value
+    >>> largeval = random.getrandbits(100)
+    >>> # Store the large integer value to the tree using asdf.IntegerType
+    >>> tree = dict(largeval=asdf.IntegerType(largeval))
+    >>> with asdf.AsdfFile(tree) as af:
+    ...     af.write_to('largeval.asdf')
+    >>> with asdf.open('largeval.asdf') as aa:
+    ...     assert aa['largeval'] == largeval
+    """
+
+    name = 'core/integer'
+    version = '1.0.0'
+
+    _value_cache = dict()
+
+    def __init__(self, value, storage_type='internal'):
+        assert storage_type in ['internal', 'inline'], "Invalid storage type given"
+        self._value = value
+        self._sign = '-' if value < 0 else '+'
+        self._storage = storage_type
+
+    @classmethod
+    def to_tree(cls, node, ctx):
+
+        if ctx not in cls._value_cache:
+            cls._value_cache[ctx] = dict()
+
+        abs_value = int(np.abs(node._value))
+
+        # If the same value has already been stored, reuse the array
+        if abs_value in cls._value_cache[ctx]:
+            array = cls._value_cache[ctx][abs_value]
+        else:
+            # pack integer value into 32-bit words
+            words = []
+            value = abs_value
+            while value > 0:
+                words.append(value & 0xffffffff)
+                value >>= 32
+
+            array = np.array(words, dtype=np.uint32)
+            if node._storage == 'internal':
+                cls._value_cache[ctx][abs_value] = array
+
+        tree = dict()
+        ctx.set_array_storage(array, node._storage)
+        tree['words'] = custom_tree_to_tagged_tree(array, ctx)
+        tree['sign'] = node._sign
+        tree['string'] = str(int(node._value))
+
+        return tree
+
+    @classmethod
+    def from_tree(cls, tree, ctx):
+
+        value = 0
+        for x in tree['words'][::-1]:
+            value <<= 32
+            value |= int(x)
+
+        if tree['sign'] == '-':
+            value = -value
+
+        return IntegerType(value)
+
+    def __int__(self):
+        return int(self._value)
+
+    def __float__(self):
+        return float(self._value)
+
+    def __eq__(self, other):
+        if isinstance(other, Integral):
+            return self._value == other
+        elif isinstance(other, IntegerType):
+            return self._value == other._value
+        else:
+            raise ValueError(
+                "Can't compare IntegralType to unknown type: {}".format(
+                    type(other)))
+
+    def __repr__(self):
+        return "IntegerType({})".format(self._value)
diff --git a/asdf/tags/core/tests/test_integer.py b/asdf/tags/core/tests/test_integer.py
new file mode 100644
index 000000000..5b171f966
--- /dev/null
+++ b/asdf/tags/core/tests/test_integer.py
@@ -0,0 +1,93 @@
+# Licensed under a 3-clause BSD style license - see LICENSE.rst
+# -*- coding: utf-8 -*-
+
+import random
+
+import pytest
+
+import asdf
+from asdf import IntegerType
+from asdf.tests import helpers
+
+
+# Make sure tests are deterministic
+random.seed(0)
+
+
+@pytest.mark.parametrize('sign', ['+', '-'])
+@pytest.mark.parametrize('value', [
+    random.getrandbits(64),
+    random.getrandbits(65),
+    random.getrandbits(100),
+    random.getrandbits(128),
+    random.getrandbits(129),
+    random.getrandbits(200),
+])
+def test_integer_value(tmpdir, value, sign):
+
+    if sign == '-':
+        value = -value
+
+    integer = IntegerType(value)
+    tree = dict(integer=integer)
+    helpers.assert_roundtrip_tree(tree, tmpdir)
+
+
+@pytest.mark.parametrize('inline', [False, True])
+def test_integer_storage(tmpdir, inline):
+
+    tmpfile = str(tmpdir.join('integer.asdf'))
+
+    kwargs = dict()
+    if inline:
+        kwargs['storage_type'] = 'inline'
+
+    random.seed(0)
+    value = random.getrandbits(1000)
+    tree = dict(integer=IntegerType(value, **kwargs))
+
+    with asdf.AsdfFile(tree) as af:
+        af.write_to(tmpfile)
+
+    with asdf.open(tmpfile, _force_raw_types=True) as rf:
+        if inline:
+            assert 'source' not in rf.tree['integer']['words']
+            assert 'data' in rf.tree['integer']['words']
+        else:
+            assert 'source' in rf.tree['integer']['words']
+            assert 'data' not in rf.tree['integer']['words']
+
+        assert 'string' in rf.tree['integer']
+        assert rf.tree['integer']['string'] == str(value)
+
+
+def test_integer_storage_duplication(tmpdir):
+
+    tmpfile = str(tmpdir.join('integer.asdf'))
+
+    random.seed(0)
+    value = random.getrandbits(1000)
+    tree = dict(integer1=IntegerType(value), integer2=IntegerType(value))
+
+    with asdf.AsdfFile(tree) as af:
+        af.write_to(tmpfile)
+        assert len(af.blocks) == 1
+
+    with asdf.open(tmpfile, _force_raw_types=True) as rf:
+        assert rf.tree['integer1']['words']['source'] == 0
+        assert rf.tree['integer2']['words']['source'] == 0
+
+    with asdf.open(tmpfile) as aa:
+        assert aa.tree['integer1'] == value
+        assert aa.tree['integer2'] == value
+
+
+def test_integer_conversion():
+
+    random.seed(0)
+    value = random.getrandbits(1000)
+
+    integer = asdf.IntegerType(value)
+    assert integer == value
+    assert int(integer) == int(value)
+    assert float(integer) == float(value)
diff --git a/asdf/tests/test_schema.py b/asdf/tests/test_schema.py
index 0aa03b0d2..81b3b2c28 100644
--- a/asdf/tests/test_schema.py
+++ b/asdf/tests/test_schema.py
@@ -507,6 +507,24 @@ def test_large_literals(use_numpy):
         print(buff.getvalue())
 
 
+def test_read_large_literal():
+
+    value = 1 << 64
+    yaml = """integer: {}""".format(value)
+
+    buff = helpers.yaml_to_asdf(yaml)
+
+    with pytest.warns(UserWarning) as w:
+        with asdf.open(buff) as af:
+            assert af['integer'] == value
+
+        # We get two warnings: one for validation time, and one when defaults
+        # are filled. It seems like we could improve this architecture, though...
+        assert len(w) == 2
+        assert str(w[0].message).startswith('Invalid integer literal value')
+        assert str(w[1].message).startswith('Invalid integer literal value')
+
+
 def test_nested_array():
     s = {
         'type': 'object',
diff --git a/asdf/versioning.py b/asdf/versioning.py
index 00a92997e..f87c637ce 100644
--- a/asdf/versioning.py
+++ b/asdf/versioning.py
@@ -132,15 +132,15 @@ def __hash__(self):
         return super(AsdfSpec, self).__hash__()
 
 
-default_version = AsdfVersion('1.2.0')
-
-
 supported_versions = [
     AsdfVersion('1.0.0'),
     AsdfVersion('1.1.0'),
-    AsdfVersion('1.2.0')
+    AsdfVersion('1.2.0'),
+    AsdfVersion('1.3.0')
 ]
 
+default_version = supported_versions[-1]
+
 
 class VersionedMixin(object):
     _version = default_version
diff --git a/docs/asdf/features.rst b/docs/asdf/features.rst
index 3b8d537a8..77f916375 100644
--- a/docs/asdf/features.rst
+++ b/docs/asdf/features.rst
@@ -18,6 +18,19 @@ respectively. The top-level tree object behaves like a Python dictionary and
 supports arbitrary nesting of data structures. For simple examples of creating
 and reading trees, see :ref:`overview`.
 
+.. note::
+
+   The ASDF Standard imposes a maximum size of 52 bits for integer literals in
+   the tree (see `the docs <https://asdf-standard.readthedocs.io/en/latest/known_limits.html#literal-integer-values-in-the-tree>`_
+   for details and justification). Attempting to store a larger value will
+   result in a validation error.
+
+   Integers and floats of up to 64 bits can be stored inside of :mod:`numpy`
+   arrays (see below).
+
+   For arbitrary precision integer support, see `IntegerType`.
+
+
 One of the key features of ASDF is its ability to serialize :mod:`numpy`
 arrays. This is discussed in detail in :ref:`array-data`.