The changes in June were dominated by the revamping of Manual of Style (dates and numbers) guidelines on such areas as scientific notation, binary prefixes, and units of measurement. For feedback and any corrections that are required, please leave a note here. All monthly updates from the start of this year are listed here.

There were major changes to the guidelines on scientific notation, engineering notation, and uncertainty; binary prefixes; and units of measurement.

Non-breaking spaces. The narrower scope for using non-breaking (i.e., "hard") spaces was significantly clarified. They should be used:

• in compound expressions in which figures and abbreviations or symbols are separated by a space (17 kg, AD 565, 2:50 pm);
• between month and day in dates that are not autoformatted (August 3, 1979);
• on the left side of spaced en dashes; and
• in other places where displacement might be disruptive to the reader, such as £11 billion, 5° 24′ 21.12″ N, Boeing 747, and the first two items in 7 World Trade Center.

Instability: The large number of edits during this month has caused disquiet among contributors. Because many of these changes may be subsumed by an audit for copy-editing and other issues during July, the details are not listed here.

Establish context. The following sentence was added:

Where an article title is of the type "List of ...", the repetition of the title in the first line should generally be avoided in favour of providing readers with useful information about the context of the list.

Why sources should be cited. This was added:

The citation should state, as clearly, fully, and precisely as possible, how a reader can find the source material, such as by external link to the source website. If the material is not findable online, it should be findable in reputable libraries, archives, or collections. If a citation without an external link is challenged as unfindable, any of the following is sufficient to show the material to be reasonably findable (though not necessarily reliable): providing an ISBN or OCLC number; linking to an established Wikipedia article about the source (the work, its author, or its publisher); or directly quoting the material on the talk page, briefly and in context.

When to cite sources. The last sentence was added:

The list of featured-article criteria calls for citations where appropriate. This page clarifies that requirement. This list is not exhaustive, and the examples are suggestions only. Each case must be dealt with on its merits.

When adding material that is challenged or likely to be challenged. This was added:

Opinions, data and statistics, and statements based on someone's scientific work should be cited and attributed to their authors in the text.

Reference qualification in article text. This text:

A statement open to controversy, regarding which the qualified supporting references conflict with one another, may need to include some elaboration.

was changed to:

... points which are more controversial, where there are contradictory studies or different opinions, may need to include more descriptive context.

Provide full citations. The underlined words were added:

Citations for newspaper articles typically include the title of the article in quotes, the byline (author's name), the name of the newspaper in italics, date of publication, page number(s), and a comment with the date you retrieved it if it is online (invisible to the reader).

Embedded links. The second sentence was added:

A full citation is also required in a References section at the end of the article. Providing an access date for the link in a comment helps editors recover a link that has become unavailable.

The instructions on capping by reviewers were amended by adding a second sentence (underlined):

"Alternately, reviewers may hide lengthy, resolved commentary in a cap template with a signature in the header. This method should be used sparingly, because it can cause the FAC archives to exceed template limits.

In a significant change, this rule:

For listing, if a sound is listed here for seven days with four or more supporting votes (including the nominator if it was not a self-nomination), and the general consensus is in its favor, it can be added to a Wikipedia:Featured sounds list. If necessary, decisions about close votes will be made on a case-by-case basis.

was changed to this:

If a nomination is listed here for 14 days with three or more supporting declarations and the general consensus is in its favor, it can be added to a Wikipedia:Featured sounds list.

WP:NFCC#8. The last clause was again removed, having been removed and reinstated in previous months:

Significance. Non-free content is used only if its presence would significantly increase readers' understanding of the topic, and its omission would be detrimental to that understanding.