An experimental version of APFS, with some limitations, is availableprovided in [[macOS Sierra]] 10.12.4. It is available through the command line <code>diskutil</code> utility. Among these limitations, it does not perform [[Unicode normalization]] while HFS+ does,<ref>{{Cite web|url=https://mjtsai.com/blog/2017/03/24/apfss-bag-of-bytes-filenames/|title=Michael Tsai - Blog - APFS’s “Bag of Bytes” Filenames|first=Michael J.|last=Tsai}}</ref> leading to problems with languages other than English.<ref>{{Cite web|url=https://eclecticlight.co/2017/04/06/apfs-is-currently-unusable-with-most-non-english-languages/|title=APFS is currently unusable with most non-English languages|date=April 6, 2017|archive-url=https://web.archive.org/web/20170608180050/https://eclecticlight.co/2017/04/06/apfs-is-currently-unusable-with-most-non-english-languages/|archive-date=June 8, 2017|url-status=live}}</ref> Drives formatted with Sierra’s version of APFS may also not be compatible with futurelater versions of macOS or the final version of APFS, and the Sierra version of APFS cannot be used with [[Time Machine (macOS)|Time Machine]], FileVault volumes, or Fusion Drives.<ref name=":0">{{Cite news|url=http://www.howtogeek.com/272741/how-to-format-a-drive-with-the-apfs-file-system-on-macos-sierra/|title=How to Format a Drive With the APFS File System on macOS Sierra|access-date=October 26, 2016|url-status=live|archive-url=https://web.archive.org/web/20161026171416/http://www.howtogeek.com/272741/how-to-format-a-drive-with-the-apfs-file-system-on-macos-sierra/|archive-date=October 26, 2016|df=mdy-all}}</ref>▼
Limited, experimental support for APFS was first introduced in [[macOS Sierra]] 10.12.4. Since [[macOS High Sierra | macOS 10.13 High Sierra]], all devices with flash storage are automatically converted to APFS.<ref name=prepForAPFS>{{cite web | url=https://support.apple.com/en-gb/HT208018 | title=Prepare for APFS in macOS High Sierra | work=Apple.com | date=September 7, 2017 | access-date=September 19, 2017 | df=mdy-all}}</ref> As of [[macOS Mojave | macOS 10.14 Mojave]], [[Fusion Drive]]s and hard disk drives are also upgraded on installation.<ref>{{cite web | url=https://arstechnica.com/features/2018/09/macos-10-14-mojave-the-ars-technica-review/3/ | title=macOS 10.14 Mojave: The Ars Technica review | work=arstechnica.com | date=September 25, 2018 | access-date=December 20, 2018 | df=mdy-all}}</ref> The primary user interface to upgrade does not present an option to opt out of this conversion, and devices formatted with the High Sierra version of APFS will not be readable in previous versions of macOS.<ref name=prepForAPFS /> Users can disable APFS conversion by using the installer's <code>startosinstall</code> utility on the command line and passing <code>--converttoapfs NO</code>.<ref>{{cite web|last1=Trouton|first1=Rich|title=Using the macOS High Sierra OS installer's startosinstall tool to avoid APFS conversion|url=https://derflounder.wordpress.com/2017/09/26/using-the-macos-high-sierra-os-installers-startosinstall-tool-to-avoid-apfs-conversion/|website=Der Flounder|access-date=January 16, 2018|date=September 26, 2017|df=mdy-all}}</ref>
[[FileVault]] volumes are not converted to APFS as of macOS Big Sur 11.2.1. Instead macOS formats external FileVault drives as CoreStorage Logical Volumes formatted with Mac OS Extended (Journaled). FileVault drives can be optionally encrypted.{{fact|date=February 2021}}
▲An experimental version of APFS, with some limitations, is available in [[macOS Sierra]] through the command line <code>diskutil</code> utility. Among these limitations, it does not perform [[Unicode normalization]] while HFS+ does,<ref>{{Cite web|url=https://mjtsai.com/blog/2017/03/24/apfss-bag-of-bytes-filenames/|title=Michael Tsai - Blog - APFS’s “Bag of Bytes” Filenames|first=Michael J.|last=Tsai}}</ref> leading to problems with languages other than English.<ref>{{Cite web|url=https://eclecticlight.co/2017/04/06/apfs-is-currently-unusable-with-most-non-english-languages/|title=APFS is currently unusable with most non-English languages|date=April 6, 2017|archive-url=https://web.archive.org/web/20170608180050/https://eclecticlight.co/2017/04/06/apfs-is-currently-unusable-with-most-non-english-languages/|archive-date=June 8, 2017|url-status=live}}</ref> Drives formatted with Sierra’s version of APFS may also not be compatible with future versions of macOS or the final version of APFS, and the Sierra version of APFS cannot be used with [[Time Machine (macOS)|Time Machine]], FileVault volumes, or Fusion Drives.<ref name=":0">{{Cite news|url=http://www.howtogeek.com/272741/how-to-format-a-drive-with-the-apfs-file-system-on-macos-sierra/|title=How to Format a Drive With the APFS File System on macOS Sierra|access-date=October 26, 2016|url-status=live|archive-url=https://web.archive.org/web/20161026171416/http://www.howtogeek.com/272741/how-to-format-a-drive-with-the-apfs-file-system-on-macos-sierra/|archive-date=October 26, 2016|df=mdy-all}}</ref>
