How does versioning work in a list or library?

When versioning is enabled in your list or library, you can store, track, and restore items in a list and files in a library whenever they change. Versioning, combined with other settings, such as checkout, gives you a lot of control of the content that is posted on your site and can provide real value if you ever have a need to look at or restore an old version of an item or file.

Versioning overview

Anyone with permission to manage lists can turn versioning on or off for a library. Versioning is available for list items in all default list types—including calendars, issue tracking lists, and custom lists. It is also available for all file types that can be stored in libraries, including Web Part pages. See Enable and configure versioning for a list or library for more info on setting up and using versioning.

Note:  If you are an Office 365 customer, versioning is now turned on by default when you create new OneDrive for Business libraries, and it will automatically save the last ten versions of a document. This will help you prevent losing important documents or data. If you have existing libraries on your OneDrive for Business site or on your team site that do not have versioning enabled, you can turn versioning on for them at any time.

You can use versioning to:

• Track history of a version    When versioning is enabled, you can see when an item or file was changed and who changed it. You can also see when properties (information about the file) were changed. For example, if someone changes the due date of a list item, that information appears in the version history. You can also see the comments people make when they check files into libraries.

• Restore a previous version    If you made a mistake in a current version, if the current version is corrupt, or if you simply like a previous version better, you can replace the current version with a previous one. The restored version becomes the new current version.

• View a previous version    You can view a previous version without overwriting your current version. If you are viewing version history within a Microsoft Office document, such as a Word or Excel file, you can compare the two versions to determine what the differences are.

When versions are created

When versioning is enabled, versions are created in the following situations:

• When a list item or file is first created or when a file is uploaded.

  Note:  If file checkout is required, you have to check the file in to create its first version.

• When a file is uploaded that has the same name as an existing file and the Add as a new version to existing files check box is selected.

• When the properties of a list item or file are changed.

• When a file is opened, edited, and saved. A version is created when you first click Save. It retains the new version number for the duration of the current editing session, even though you might save it several times. When you close it and then reopen it for another editing session, another version is created.

• During co-authoring of a document, when a different user begins working on the document or when a user clicks save to upload changes to the library. The default time period for creating new versions during co-authoring is 30 minutes. This is configurable per web application in SharePoint on-premises. This setting is not configurable in SharePoint Online.

There can be up to three current versions of a file at any given time: the checked-out version, the latest minor or draft version, and the latest published or major version. All other versions are considered historical versions. Some current versions are only visible to users who have permissions to view them.

Major and minor versions

Some organizations track both major and minor versions of files in their libraries. Others only track the major versions. Major versions are identified by whole numbers, such as 5.0; minor versions are identified by decimal numbers, such as 5.1.

Most organizations use minor versions when files are under development, and major versions when certain milestones are reached or when the files are ready for review by a wide audience. In many organizations, draft security is set to allow only the owner of a file and people who have permissions to approve files. That means that minor versions cannot be seen by anyone else until a major version is published.

Major versions are available for lists, but minor versions are not available. Each version of a list item is numbered with a whole number. If your organization requires approval of items in a list, the items remain in Pending status until they are approved by someone who has permissions to approve them. While in Pending status they are numbered with decimal numbers and are referred to as drafts.

Version numbering

Version numbers are automatically added each time you create a new version. In a list or library that has major versioning enabled, the versions have whole numbers, such as 1.0, 2.0, 3.0, and so on. In libraries, your administrator might enable versioning for both major and minor versions. When minor versions are being tracked, they have decimal numbers such as 1.1, 1.2, 1.3, and so on. When one of those versions is published as a major version, its number becomes 2.0. Subsequent minor versions are numbered 2.1, 2.2, 2.3, and so on.

When you discard a checkout, the version number does not change. If the most recent version was version 3.0, it remains at 3.0 after you discard the checkout.

When you delete a version, the version goes to the Recycle Bin and its number goes with it. The Version History will show the remaining version numbers. The other version numbers do not change. For example, if you have a document that has minor versions 4.1 and 4.2, and you decide to delete version 4.1, the resulting version history shows only versions 4.0 and 4.2. The following picture shows this.

Is there any limit to the number of available versions?

Some organizations allow unlimited versions of files and others apply limitations. You might discover, after checking in the latest version of a file, that an old version is missing. If your most recent version is 26.0 and you notice that there is no longer a version 1.0, it means that the administrator configured the library to allow only 25 major versions of a file. The addition of the 26th version causes the first version to be deleted. Only versions 2.0 through 26.0 remain. Similarly, if a 27th version is added, only versions 3.0 through 27.0 remain.

The administrator may also decide to limit the number of minor versions to just those for a set number of the most recent versions. For example, if 25 major versions are allowed, the administrator might decide to retain minor drafts for only the most recent five major versions. The default number of minor versions between major versions is 512. If you attempt to save another minor version, you will see an error message that tells you that you must first publish the document. Your site administrator can change the default to allow fewer minor versions.

Limiting the number of versions is generally a good practice. It means you can conserve space on the server and reduce clutter for users. But, if your organization is required to save all versions for legal or other reasons, don't apply any limits.

Enabling, configuring, and using versioning in lists and libraries

Versioning is not turned on automatically when a list or library is created, but anyone with permission to manage lists can turn on versioning. On many sites that is the same person who manages the site, because the lists and libraries inherit permissions from the site. In addition to enabling versioning, the site owner (or another person managing the list or library) decides whether or not to require content approval, who can view draft items, and whether or not checkout is required. Each of these decisions has an impact on how versioning works. For example, if the person managing a library decides to require check-out, version numbers are only created when a file is checked in. If content approval is required, major version numbers are not applied until files are approved by someone who has permission to do so.

Important:  If the people who work in your library are planning to co-author documents, do not configure the library to require check-out. People cannot work as co-authors when the documents that they need are checked out.

To learn how to turn on versioning for a list or library, see Enable and configure versioning for a list or library.

How does versioning work with required content approval?

If versioning is enabled in your library, the person who sets it up determines whether or not to track both major and minor versions and also determines who can see the minor versions. In most cases, when content approval is required, only the owner of the file, and people who have permission to approve items, can see the minor versions. In other libraries, anyone who can edit files in the library, or anyone who has Read permission to the library, can see all versions. After a version is approved, everyone who has Read permission to the list or library can see the version.

Although lists do not have major and minor versions, any item that is in Pending status is considered a draft. In most cases, only the creator of the item and persons who have Full Control or Design permissions can see drafts. A draft shows up in Pending status for those people, but others only see the most recent Approved version in the version history. If the file is rejected, it stays in Pending status until someone who has the necessary permissions deletes it.

Note:  Draft security, in some lists and libraries, is configured to allow all site users to see both Pending and Approved versions.

How does versioning work with file checkout?

When you check out a file from a library that has versioning turned on, a new version is created every time you check it back in. And, if major and minor versions are turned on, you can decide, at check-in, which type of version you are checking in. In libraries where checkout is required, versions are only created upon check-in.

In libraries where checkout is not required, a new version is created the first time you save after opening the file. Each subsequent save overwrites the version that you created with the first save. If you close the application and then reopen the document, the first save will, once again, produce a version. This can cause the number of versions to proliferate very rapidly.

Important:  If you are co-authoring a document, do not check it out unless you have good reason to prevent others from working on the document.