Like any SharePoint document library, you can enable versioning and display the document version number field in the library web part view. 

To display the the WikiPlus document version on a WikiPlus page follow the steps below:

1. add the following block of code to the WikiPlusTemplates.aspx file located on your front end SharePoint 2013 server in C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\15\TEMPLATE\CONTROLTEMPLATES:

<tr>
<th nowrap="nowrap" valign="top">
<h3 class="ms-standardheader">
<SharePoint:FieldLabel ID="FieldLabel_UIVersionString" FieldName="_UIVersionString" runat="server" />
:</h3>
</th>
<td nowrap="nowrap" valign="top">
<SharePoint:FormField ID="FormField_UIVersionString" ControlMode="Display" FieldName="_UIVersionString" runat="server" />
</td>
</tr>

Ex:

2. Perform an IISRESET
3. Repeating steps 1-2 on each front end server in your farm

Note: make sure no copies of WikiPlusTemplate.aspx file is in the same controltemplate folder as the original.  This will cause issues. 

 Ex: you make made a backup copy and rename the filename.