TEI P5 version 4.0.0 Release 4.0.0 is codenamed‘Galileo’in honor of Galileo's arrival to Rome on 13 February 1633 to face the Inquisition. We associate Galileo with decentering the earth in official western dogma of the universe. Similarly, the stand-off model in this release of the TEI Guidelines may serve to decenter our models of digital texts and expand our frames of reference. With the addition ofstandOff, a significant change in how characters outside of Unicode are described, and the ability ofTEIto self-nest, this version is significantly different than previous versions, and thus deserves an increase in the “major” release number. In addition to the stand-off model, this release introduces new features and resolves a number of issues raised by the TEI community. As always, the majority of these changes and corrections are a consequence of feature requests or bugs reported by the TEI community using the GitHub tracking system. A full list of the issues resolved in the course of this release cycle may be found under the4.0.0 milestone. The following changes are particularly worth highlighting in this release: ThestandOffelement functions as a container element for linked data, contextual information, and stand-off annotations embedded in a TEI document (#374, thanks to Laurent Romary and Piotr Bański). With the introduction of thestandOffelement a new structural classmodel.describedResourcehas been introduced, andmodel.resourceLikehas been revised and renamedmodel.resource. As theTEIelement is a member of the newmodel.describedResourceclass, it can now be a child of anotherTEIelement. The newstandOffelement: is a child ofTEI(orteiCorpus); may contain stand-off annotations, for example morphosyntactic annotations encoded withspanGrporannotationBlock; may contain stand-off markup, for example a series ofcertainty,linkGrp, oraltelements; may contain contextual information, for examplelistPersonandlistPlace; may contain information that must be pointed to from elsewhere, but is not found in the source document, for example acastListthat represents characters who speak in a drama, but whose roles are not listed in the source document's printed cast list. New elements, attributes, and an attribute class have been introduced for using Unihan properties in TEI (#1805, thanks to Duncan Paterson): The attribute classatt.gaijiPropprovides attributes for defining the properties of non-standard characters or glyphs. Thenameattribute provides the name of the character or glyph property being defined. Thevalueattribute provides the value of the character or glyph property being defined. Theversionattribute specifies the version number of the Unicode Standard in which this property name is defined. A list of suggested values is provided. ThelocalPropelement provides a locally defined character (or glyph) property. TheunicodePropelement provides a Unicode property for a character (or glyph). TheunihanPropelement holds the name and value of a normative or informative Unihan character (or glyph) property as part of its attributes. A list of legal values from theUnicode Han Databaseis provided for thenameattribute onunihanProp. The use of the elementscharProp,charName,localName,unicodeName, andvaluehas been deprecated. Changes were made to improve the precision of language in the Guidelines referring to conformance (#1588) Multiple Schematron rules, assertions, or reports in a singleconstraintSpecare now correctly output as a singlesch:patternin the RELAX NG schemas (#1625). The discussion of validation has been updated inA Gentle Introduction to XML(#1708). The attributesmodeandidenthave been added to theremarkselement (#1713). The elementsdecoNote,explicit, andincipitare now members of themodel.biblPartclass (#1784). The description of thepointsattribute inatt.coordinatedhas been clarified (#1789). Thexrelement is now a member of the attribute classatt.typed(#1810). Our use of the Travis continuous integration server has been migrated from travis.org to travis.com (#1826). An example to specify the source of a translation has been added (#1830). The description of manuscript descriptions clarifies thatmsDesccan be used for all text-bearing objects (#1835). The content model ofrepository,institution, andcollectionhas been changed frommacro.xtexttomacro.phraseSeq.limited(#1836). Thegelement is now available within thezoneelement (#1838). TheplaceNameelement has been added to the classmodel.settingPartand the example in thesettingelement has been changed accordingly (#1842). Thedatelineelement is now a member of the classmodel.pLike.front(#1843). ThecatDescelement is now a member of the attribute classatt.canonical(#1864). A Schematron rule has been added to only allow oneremarkselement per language in specification files (#1872). The datatype of thenameattribute of theattRefelement has been changed fromteidata.texttoteidata.name(#1878). The schema has been tightened to prevent a combination ofvalListin sequence with other members ofmodel.contentPart(#1862). With the addition of thesubtypeattribute to the attribute classatt.textCritical,subtypeis now available onlem,rdg, andrdgGrp(#1867). The content model ofteiCorpushas been changed (#1922). The constraints for teidata.word have been loosened to allow any character except Unicode separators or control characters (#1930). The explanation of Relax NG and XPath, together with its associated graphic in the chapterA Gentle Introduction to XMLhave been revised (#1949). Corrections of typographic errors and broken links, improvements on explanations, and corrections of examples have been conducted in various sections of the Guidelines (including#1760,#1847,#1887,#1907,#1909,#1927,#1936,#1948,#1952,#1954,#1964,#1965,#1968,#1969). Furthermore, a number of translations have been added or updated. In addition, many improvements have been made to the XSLT stylesheets (which provide processing of TEI ODD files forRomaandOxGarageas well as other TEI conversions). The Stylesheets are maintained separately from the Guidelines athttps://github.com/TEIC/Stylesheets. A full list of the issues resolved in the course of this release cycle may be found under the7.49.0 milestone. Highlights of this release include: Thetypeattribute onbiblScopehas been replaced by theunitattribute in the tests (#213). Orphaned files in the test directory have been removed (#216). Relative paths to CSS files in the EPUB transformation have been replaced with absolute paths (#312). The jquery library has been updated (#359). Special characters encoded as in DOCX are now converted tohielements (#389). Correct handling of Schematron rules inattDefelements (#403and#1950). Finally, we have made some significant updates to our documentation and the website: Documentation of Council practices inTCW 20is improved for working with branches in the TEIC GitHub repository#1825. The documentation for updating the TEI Framework in oXygen to the latest release of the TEI Guidelines has been improved#1673and added to the oxygen-tei repository, seeHow to automatically update your TEI framework in oXygen. Corrections have been conducted in various sections of the TEI website (including#1944), and#1938.