diff --git a/src/SoftwareApplication.ts b/src/SoftwareApplication.ts
index 19e6f48e9d..14d79589b6 100644
--- a/src/SoftwareApplication.ts
+++ b/src/SoftwareApplication.ts
@@ -7,7 +7,7 @@ import { Text } from './dataTypes'
 
 /**
  * A software application.
- * 
+ *
  * @see {@link https://schema.org/SoftwareApplication}
  */
 @type('schema:SoftwareApplication')
@@ -15,7 +15,7 @@ export default class SoftwareApplication extends CreativeWork {
 
   /**
    * Type of software application, e.g. 'Game, Multimedia'.
-   * 
+   *
    * @see {@link https://schema.org/applicationCategory}
    */
   @property('schema:applicationCategory')
@@ -23,7 +23,7 @@ export default class SoftwareApplication extends CreativeWork {
 
   /**
    * Subcategory of the application, e.g. 'Arcade Game'.
-   * 
+   *
    * @see {@link https://schema.org/applicationSubCategory}
    */
   @property('schema:applicationSubCategory')
@@ -31,7 +31,7 @@ export default class SoftwareApplication extends CreativeWork {
 
   /**
    * Operating systems supported (Windows 7, OSX 10.6, Android 1.6).
-   * 
+   *
    * @see {@link https://schema.org/operatingSystem}
    */
   @property('schema:operatingSystem')
@@ -41,27 +41,13 @@ export default class SoftwareApplication extends CreativeWork {
    * Component dependency requirements for application.
    * This includes runtime environments and shared libraries that are not included in
    * the application distribution package, but required to run the application.
-   * 
+   *
    * The [`schema:softwareRequirements`](https://schema.org/softwareRequirements)
    * property allows for `Text` or `URL` values. Here, we allow
    * values of software packages or applications.
-   * 
+   *
    * @see {@link https://schema.org/softwareRequirements}
    */
   @property('schema:softwareRequirements')
   softwareRequirements: Array<SoftwarePackage | SoftwareApplication> = []
-
-  // These properties were added for use in Dockter `PythonParser`
-  //     https://github.com/stencila/dockter/blob/v0.12.1/src/PythonParser.ts#L188
-  // But see this discussion for an alternative approach:
-  //     https://github.com/stencila/schema/issues/4
-
-  @property('schema:codeRepository')
-  codeRepository: Text | URL = ''
-
-  @property('schema:programmingLanguage')
-  programmingLanguages: Array<ComputerLanguage> = []
-
-  @property('schema:runtimePlatform')
-  runtimePlatform: Text = ''
 }
diff --git a/src/SoftwarePackage.ts b/src/SoftwarePackage.ts
index 43c2a689f6..7368420c95 100644
--- a/src/SoftwarePackage.ts
+++ b/src/SoftwarePackage.ts
@@ -3,24 +3,58 @@ import SoftwareApplication from './SoftwareApplication'
 import SoftwareSourceCode from './SoftwareSourceCode'
 
 /**
- * An extension class defined for this context to represent a software package.
+ * A software package.
  *
- * This is necessary because `schema:SoftwareSourceCode`
- * has most properties needed to represent a package but not all of them.
+ * This is an extension class defined for this context.
+ * It is necessary because `schema:SoftwareSourceCode`
+ * has most, but not all, of the properties that we need to represent a package,
+ * for applications such as Dockter.
  * Meanwhile, `schema:SoftwareApplication` has some of those missing
- * properties but lacks most of those needed. Thus, this type does
+ * properties but lacks most. This type does
  * not introduce any new properties, but rather uses
  * schema.org properties on a subtype of `schema:SoftwareSourceCode`
+ *
+ * An alternative approach would be to create a `SoftwareApplication` which
+ * links to one or more `SoftwarePackages`. See https://github.com/codemeta/codemeta/issues/198
  */
 @type('stencila:SoftwarePackage')
 export default class SoftwarePackage extends SoftwareSourceCode {
 
   /**
+   * Type of software application, e.g. 'Game, Multimedia'.
+   *
+   * @see {@link https://schema.org/applicationCategory}
+   */
+  @property('schema:applicationCategory')
+  applicationCategories: Array<Text | URL> = []
+
+  /**
+   * Subcategory of the application, e.g. 'Arcade Game'.
+   *
+   * @see {@link https://schema.org/applicationSubCategory}
+   */
+  @property('schema:applicationSubCategory')
+  applicationSubCategories: Array<Text | URL> = []
+
+  /**
+   * Operating systems supported (Windows 7, OSX 10.6, Android 1.6).
+   *
+   * @see {@link https://schema.org/operatingSystem}
+   */
+  @property('schema:operatingSystem')
+  operatingSystems: Array<OperatingSystem> = []
+
+  /**
+   * Component dependency requirements for application.
+   * This includes runtime environments and shared libraries that are not included in
+   * the application distribution package, but required to run the application.
+   *
    * The [`schema:softwareRequirements`](https://schema.org/softwareRequirements)
    * property allows for `Text` or `URL` values. Here, we allow
    * values of software packages or applications.
+   *
+   * @see {@link https://schema.org/softwareRequirements}
    */
   @property('schema:softwareRequirements')
   softwareRequirements: Array<SoftwarePackage | SoftwareApplication> = []
-
 }