update .ipynb files with correct references. update package requirements

docs/guide/custom.ipynb

@@ -537,7 +537,7 @@
    "source": [
     "### Custom STIX Object Types\n",
     "\n",
-    "To create a custom STIX object type, define a class with the @[CustomObject](../api/stix2.v20.sdo.rst#stix2.v20.sdo.CustomObject) decorator. It takes the type name and a list of property tuples, each tuple consisting of the property name and a property instance. Any special validation of the properties can be added by supplying an ``__init__`` function.\n",
+    "To create a custom STIX object type, define a class with the @[CustomObject](../api/v20/stix2.v20.sdo.rst#stix2.v20.sdo.CustomObject) decorator. It takes the type name and a list of property tuples, each tuple consisting of the property name and a property instance. Any special validation of the properties can be added by supplying an ``__init__`` function.\n",
     "\n",
     "Let's say zoo animals have become a serious cyber threat and we want to model them in STIX using a custom object type. Let's use a ``species`` property to store the kind of animal, and make that property required. We also want a property to store the class of animal, such as \"mammal\" or \"bird\" but only want to allow specific values in it. We can add some logic to validate this property in ``__init__``."
    ]
@@ -841,7 +841,7 @@
    "source": [
     "### Custom Cyber Observable Types\n",
     "\n",
-    "Similar to custom STIX object types, use a decorator to create [custom Cyber Observable](../api/stix2.v20.observables.rst#stix2.v20.observables.CustomObservable) types. Just as before, ``__init__()`` can hold additional validation, but it is not necessary."
+    "Similar to custom STIX object types, use a decorator to create [custom Cyber Observable](../api/v20/stix2.v20.observables.rst#stix2.v20.observables.CustomObservable) types. Just as before, ``__init__()`` can hold additional validation, but it is not necessary."
    ]
   },
   {
@@ -1163,7 +1163,7 @@
    "source": [
     "### Custom Cyber Observable Extensions\n",
     "\n",
-    "Finally, custom extensions to existing Cyber Observable types can also be created. Just use the @[CustomExtension](../api/stix2.v20.observables.rst#stix2.v20.observables.CustomExtension) decorator. Note that you must provide the Cyber Observable class to which the extension applies. Again, any extra validation of the properties can be implemented by providing an ``__init__()`` but it is not required. Let's say we want to make an extension to the ``File`` Cyber Observable Object:"
+    "Finally, custom extensions to existing Cyber Observable types can also be created. Just use the @[CustomExtension](../api/v20/stix2.v20.observables.rst#stix2.v20.observables.CustomExtension) decorator. Note that you must provide the Cyber Observable class to which the extension applies. Again, any extra validation of the properties can be implemented by providing an ``__init__()`` but it is not required. Let's say we want to make an extension to the ``File`` Cyber Observable Object:"
    ]
   },
   {

docs/guide/datastore.ipynb

@@ -454,7 +454,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "##### Note: The `defanged` property is now always included (implicitly) for STIX 2.1 Cyber Observable Objects (SCOs)\n",
+    "**Note: The `defanged` property is now always included (implicitly) for STIX 2.1 Cyber Observable Objects (SCOs)**\n\n",
     "This is important to remember if you are writing a filter that involves checking the `objects` property of a STIX 2.1 `ObservedData` object. If any of the objects associated with the `objects` property are STIX 2.1 SCOs, then your filter must include the `defanged` property. For an example, refer to `filters[14]` & `filters[15]` in stix2/test/v21/test_datastore_filters.py "
    ]
   },
@@ -492,7 +492,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "If a STIX object has a `created_by_ref` property, you can use the [creator_of()](../api/stix2.datastore.rst#stix2.datastore.DataSource.creator_of) method to retrieve the [Identity](../api/stix2.v20.sdo.rst#stix2.v20.sdo.Identity) object that created it."
+    "If a STIX object has a `created_by_ref` property, you can use the [creator_of()](../api/stix2.datastore.rst#stix2.datastore.DataSource.creator_of) method to retrieve the [Identity](../api/v20/stix2.v20.sdo.rst#stix2.v20.sdo.Identity) object that created it."
    ]
   },
   {

docs/guide/ts_support.ipynb

@@ -365,7 +365,7 @@
    "source": [
     "### How custom content works\n",
     "\n",
-    "[CustomObject](../api/stix2.v20.sdo.rst#stix2.v20.sdo.CustomObject), [CustomObservable](../api/stix2.v20.observables.rst#stix2.v20.observables.CustomObservable), [CustomMarking](../api/stix2.v20.common.rst#stix2.v20.common.CustomMarking) and [CustomExtension](../api/stix2.v20.observables.rst#stix2.v20.observables.CustomExtension) must be registered explicitly by STIX version. This is a design decision since properties or requirements may change as the STIX Technical Specification advances.\n",
+    "[CustomObject](../api/v20/stix2.v20.sdo.rst#stix2.v20.sdo.CustomObject), [CustomObservable](../api/v20/stix2.v20.observables.rst#stix2.v20.observables.CustomObservable), [CustomMarking](../api/v20/stix2.v20.common.rst#stix2.v20.common.CustomMarking) and [CustomExtension](../api/v20/stix2.v20.observables.rst#stix2.v20.observables.CustomExtension) must be registered explicitly by STIX version. This is a design decision since properties or requirements may change as the STIX Technical Specification advances.\n",
     "\n",
     "You can perform this by:"
    ]

docs/guide/workbench.ipynb

@@ -624,7 +624,7 @@
    "source": [
     "### Creating STIX Data\n",
     "\n",
-    "To create a STIX object, just use that object's class constructor. Once it's created, add it to the workbench with [save()](../api/datastore/stix2.workbench.rst#stix2.workbench.save)."
+    "To create a STIX object, just use that object's class constructor. Once it's created, add it to the workbench with [save()](../api/stix2.workbench.rst#stix2.workbench.save)."
    ]
   },
   {
@@ -760,7 +760,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "Defaults can also be set for the [created timestamp](../api/datastore/stix2.workbench.rst#stix2.workbench.set_default_created), [external references](../api/datastore/stix2.workbench.rst#stix2.workbench.set_default_external_refs) and [object marking references](../api/datastore/stix2.workbench.rst#stix2.workbench.set_default_object_marking_refs)."
+    "Defaults can also be set for the [created timestamp](../api/stix2.workbench.rst#stix2.workbench.set_default_created), [external references](../api/stix2.workbench.rst#stix2.workbench.set_default_external_refs) and [object marking references](../api/stix2.workbench.rst#stix2.workbench.set_default_object_marking_refs)."
    ]
   },
   {

requirements.txt

@@ -1,11 +1,10 @@
 bumpversion
 ipython
-mkdocs>=1.0.4
-nbsphinx==0.3.2
+nbsphinx==0.4.3
 pre-commit
 pytest
 pytest-cov
-sphinx<1.6
+sphinx<2
 sphinx-prompt
 tox