This page identifies the principal improvements to the Creative Commons license suite since the publication of the first licenses (version 1.0) in December 2002, through the current version 4.0, published November 2013. It also highlights important similarities and differences among the major license versions. For more information on using CC tools or works offered under Creative Commons licenses, consult the Frequently Asked Questions page. For a further historical perspective, you are invited to review deprecated CC legal tools identified on the retired legal tools page.
Please note that the summaries below may not reflect all changes between license versions or fully or accurately describe the differences between them. CC cannot provide legal advice, and what follows is not legal advice. What follows below is a general description of differences and similarities between the license versions, for general informational purposes only. Consult your own attorney if you are in need of legal advice.
License Suite Versions
The chart below and linked explanations that follow detail some of the improvements and important similarities among Creative Commons license versions. Some of the explanations contain links to further information on the topic.
|License Suite Version||1.0||2.0||2.5||3.0||4.0|
|Attribution reasonable to means, medium, and context||Medium and means, with exceptions||Medium and means, with exceptions||Medium and means, with exceptions||Medium and means, with exceptions||Explicit|
|Reasonableness applies to all attribution requirements||All but license notices||All but license notices||All but license notices||All but license and copyright notices||All|
|Licensors may name other attribution parties||Implied||Implied||Implied||Explicit||Explicit|
|Licensors may request removal of attribution||Adaptations and collections only||Adaptations and collections only||Adaptations and collections only||Adaptations and collections only||Always|
|Title of work required||Yes||Yes||Yes||Yes||No|
|URI required||No||If contains copyright notice or licensing information||If contains copyright notice or licensing information||If contains copyright notice or licensing information||Yes|
|"No endorsement" clause included||No||No||No||Yes||Yes|
|Modifications must be indicated||No||No||No||Yes, but only adaptations||Yes|
Detailed attribution comparison chart
|Author if supplied||Author if supplied||Author if supplied and attribution parties if designated in copyright notice, TOS, or other reasonable means||Creator if supplied and attribution parties if designated in reasonable manner|
|Copyright notices if supplied||Copyright notices if supplied||Copyright notices if supplied||Copyright notice if supplied|
|Title if supplied||Title if supplied||Title if supplied||N/A|
|Notices that refer to Public License and the disclaimer of warranties if supplied||Notices that refer to Public License and the disclaimer of warranties if supplied||Notices that refer to Public License and the disclaimer of warranties if supplied||Notice that refers to Public License and notice that refers to the disclaimer of warranties if supplied|
|N/A||To the extent practicable, URI licensor specifies to be associated with the work (but only if references copyright notice or licensing info)||To the extent practicable, URI licensor specifies to be associated with the work (but only if references copyright notice or licensing info)||To the extent practicable, URI or link to the material if supplied|
|If adaptation, credit indicating Work has been used||If adaptation, credit indicating Work has been used||If adaptation, credit indicating Work has been used and reasonable steps taken to identify that changes were made to the original||Indicate if you modified the material; retain an indication of previous modifications|
|Text/URI for Public License||Text/URI for Public License||Text/URI for Public License||Indicate the material is available under Public License and include text/URI/link|
|If collection or adaptation, remove reference to author and licensor upon request to the extent practicable||If collection or adaptation, remove reference to author and licensor upon request to the extent practicable||If collection or adaptation, remove reference to author and licensor upon request to the extent practicable||Remove attribution information upon request to the extent reasonably practicable|
|Copyright notice, author, title, credit noting use of original in adaptation – all may be implemented in any reasonable manner, so long as at least as prominent as other authorship credit if an adaptation or collection||Copyright notice, author, title, URI, credit noting use of original in adaptation – all may be implemented in any reasonable manner, so long as at least as prominent as other authorship credit if an adaptation or collection||Author, title, URI, credit noting use of original in adaptation -- all reasonable to medium and means||All reasonable to medium, means, and context|
Features remaining unchanged
- Definition of "NonCommercial"
- Attribution required (but anonymity permitted)
- Prohibition on effective technological measures by users of CC-licensed works
- Exceptions and limitations unaffected
- License effective for all copyrightable material
- Notice of warranty disclaimers must be retained
- No sublicensing
- Synching creates adaptations
- Licensing of collections
- Licensing of BY and BY-NC adaptations
Nomenclature (for international licenses)
The 4.0 licenses are referred to as "international."
Version 3.0 licenses were referred to as "unported" licenses until 2010, at which point they were re-branded as the "international" licenses. At that point, CC added a global flag to the licenses and deeds and changed the reference in the Chooser (among other things). In the 1.0, 2.0, and 2.5 versions, the international licenses were called the “generic” licenses. The generic licenses were drafted to conform with U.S. copyright law.
Starting with version 3.0, Creative Commons drafted its core suite of licenses to conform to relevant international treaties and drafting conventions. In this sense, version 3.0 and the current 4.0 international license suites are jurisdiction-agnostic: these licenses do not mention and are not drafted against any particular jurisdiction's laws or statutes. They are intended to function without adjustment in all jurisdictions around the world.
License scope (beyond copyright)
Sui generis database rights
The 4.0 international suite licenses database rights along with copyright. Where the use of a database under a CC license implicates sui generis database rights, whether or not copyright is implicated, that use is subject to the terms and conditions of the license. If sui generis rights are not implicated—for example, if the use is in a jurisdiction where these rights do not exist, or if the database is not protected by the laws of a jurisdiction where such rights exist— such uses are not regulated by the license if copyright or neighboring rights do not apply. A few early (2.0, 2.5) European jurisdiction license ports also licensed database rights subject to the terms and conditions of the license.
In 3.0, the international (unported) license suite does not mention sui generis rights. However, ported 3.0 licenses for jurisdictions where those rights exist address them according to CC's 3.0 database rights policy. Under this policy, version 3.0 EU jurisdiction ports must license sui generis rights subject to the terms and conditions of the license just like copyright and neighboring rights, but also must waive license restrictions and conditions (attribution, ShareAlike, etc) for uses triggering database rights—so that if the use of a database published under a CC license implicated only database rights but not copyright, the CC license requirements and prohibitions would not apply to that use. The license conditions and restrictions, however, continue to apply to all uses triggering copyright. Other ports and the 3.0 international license are silent on sui generis database rights: databases and data are licensed (i.e., subject to restrictions detailed in the license) to the extent copyrightable, and if data in the database or the database itself are not copyrightable the license restrictions do not apply to those parts (though they still apply to the remainder). Thus, regardless of the CC 3.0 license at play (unported, an EU port, another port), uses that implicate only database rights will not trigger the license conditions, while uses that implicate copyright will.
Neither the international nor the ported licenses that address database rights export the sui generis rights to jurisdictions where such rights are not recognized (the ported licenses accomplish this as well through inclusion of a territoriality limitation). This avoids the imposition of restrictions based on sui generis rights via contract where those rights are not enforceable or recognized. You may compare how different jurisdictions implemented this section of the license.
Treatment of moral rights
While the existence and extent of moral rights differ by jurisdiction, the most consistently present rights are those of attribution and integrity (the right to prevent or halt the prejudicial use of one’s work by another). The 1.0, 2.0, and 2.5 licenses were drafted to conform to U.S. law, and because U.S. law recognizes moral rights in only very limited circumstances, the generic versions of those licenses suites do not address moral rights of authors.
The international licenses began to address moral rights in version 3.0. In version 4.0, moral rights are waived or not asserted to the extent possible under local law, to the limited extent they would otherwise interfere with exercise of the licensed rights. This avoids establishing moral rights through the license where they would not otherwise exist, but recognizes that there are jurisdictions where this limited waiver is not possible. The attribution requirements in Section 3 of the 4.0 licenses may satisfy many jurisdictions' right of attribution; however, they are a requirement of the license regardless of whether moral rights apply to a use.
In the 3.0 license suite, CC addressed moral rights in the international (unported) licenses. CC did not include a waiver of those rights in the international licenses. Instead, the licenses specifically instruct users that they “must not distort, mutilate, modify or take other derogatory action in relation to the Work which would be prejudicial to the Original Author's honor or reputation.” The only exception is where the right to make adaptations would be considered prejudicial to the author's honor and reputation, in which case the licensor waives or agrees not to assert their moral right in order to allow adaptations to be made. The attribution requirement is designed in part to satisfy the right of attribution. In the porting process, some jurisdictions slightly adjusted this provision, with CC’s permission, to specify that moral rights are waived to the extent necessary to effect the license to the degree a waiver is possible under applicable law. You may compare how different jurisdictions implemented this section of the license.
Trademark and patent explicitly not licensed
In the 4.0 licenses, trademark and patent rights are expressly mentioned as not among the rights licensed.
No CC license version licenses patent and trademark rights along with copyright. These rights are treated separately and are not covered by the license. In 4.0, this was made explicit to avoid confusion. However, in all license versions, implied licenses may come into play where these rights would interfere with exercise of the rights granted by the CC license.
Attribution and marking
Attribution reasonable to means, medium, and context
In 4.0, the manner of attribution is explicitly allowed to be reasonable to the means, medium, and context of how one shares a work.
In the 1.0, 2.0, 2.5, and 3.0 licenses, attribution may be reasonable to the medium or means, and applied to all elements other than certain notices where the requirement is firm. In 4.0, this explicit permission applies to the medium, means, and context of use. We believe this to be a clarification rather than a change: attribution reasonable to the means, medium, and context of use should be permissible for works under any CC license. Additionally, the pre-4.0 licenses specified that credit in adaptations and collections should be at least as prominent as credits for other authors; 4.0 is not specific in this regard.
Reasonableness applies to all attribution requirements
In 4.0, all attribution requirements may be fulfilled reasonable to the means, medium, and context of the use.
In earlier license versions, compliance reasonable to means and medium of use was not expressly permitted for all elements, as certain notices were excluded; however, in 4.0 these are included in the elements that may be fulfilled in a reasonable manner.
Credit to others explicit
In 4.0, proper attribution requires credit to designated others where supplied by the licensor.
In the 1.0 and 2.0 licenses, CC licenses contemplated crediting the author only. Versions 2.5 and 3.0 allow licensors to identify another party or organization for attribution (called an “Attribution Party” in these licenses). This feature was introduced in part to alleviate burdensome or difficult attribution situations, such as when many people contribute to a collaborative effort and agree to be credited as a collective body. In licenses with this feature, licensors may designate another party for attribution purposes—such as a sponsor institute, publishing entity or journal—in addition to or instead of the author. You may review some of the concerns raised when CC proposed this change.
Licensors may request removal of attribution
In the 4.0 licenses, a user must remove attribution from a work at the creator's request to the extent it is reasonably practicable to do so. This is true whether the work is modified or unmodified.
All license versions after version 1.0 require attribution. However, legislation in many countries gives authors the right to control the use of their name in association with their works. Therefore, CC licenses require licensees to remove attribution to the creator at his or her request, where it would otherwise be required to include it. In 2.0, 2.5, and 3.0, credit must be removed from adaptations and collections, to the extent practicable, at the creator’s request. In 4.0, the creator may also request removal of credit from the unmodified work.
The title is not required for proper attribution in the 4.0 licenses. It is required in all earlier versions.
Beginning in version 1.0, one of the requirements for proper attribution was to include the title of the licensed work; this requirement was kept in versions 2.0, 2.5, and 3.0. In Version 4.0, this requirement was eliminated to increase flexibility and ease of compliance, particularly as many works do not have titles. Users are still encouraged to include titles where supplied.
For 4.0 licensed materials, a URI is required for proper attribution, if it is reasonably practicable to include.
The version 1.0 licenses contained no URI requirement. In version 2.0, CC introduced the requirement to retain a URI associated with a licensed work for proper attribution if it contains copyright notices or licensing information; this was kept through 2.5 and 3.0. In version 4.0, CC reconsidered this requirement. However, it was retained based on feedback from current and potential adopters that it is important for provenance, branding, and other reasons; a URI associated with the work is required as part of attribution if reasonably practicable to retain, regardless of whether it contains copyright notices or licensing information.
"No endorsement" clause included
In version 4.0, the license is clear that it should not be construed as giving permission to suggest the licensor endorses their use and similar.
In some jurisdictions, wrongfully implying that an author, publisher, or anyone else endorses a particular use of a work may be unlawful. Though not explicitly mentioned in the 1.0, 2.0, or 2.5 licenses, this has always been the case. The version 3.0 licenses contain an express no endorsement clause. In version 4.0, this clause is expressed as a limitation on the rights granted by the licensor.
Modifications and adaptations must be indicated
In the 4.0 license suite, licensees are required to indicate if they made modifications to the licensed material. This obligation applies whether or not the modifications produced adapted material. As with all other attribution and marking requirements, this may be done in a manner reasonable to the means, medium, and context. For example, "This section is an excerpt of the original." For trivial modifications, such as correcting spelling errors, it may be reasonable to omit the notice.
In the 3.0 suite, the obligation to indicate if modifications have been made applies if they result in the creation of an adaptation (when allowed by the license). Versions 1.0, 2.0, and 2.5 do not contain this requirement directly; however, the requirement in those licenses that the original work be credited if used in an adaptation (e.g., "French translation of the Work by Original Author") is some indication that the work has been modified. Even when not required, licensees are encouraged to indicate the material has been modified, and ideally (when reasonable) to describe or specify the changes made.
Other license features
Representations and warranties from licensor included
In version 4.0, the licensor does not provide representations and warranties regarding the licensed content.
In the 1.0 license suite, the licensor extends warranties—for instance, that the work does not infringe the work of another. These warranties were eliminated in all subsequent license versions. Versions 2.0, 2.5, 3.0 and 4.0 explicitly offer the work “AS IS” and disclaim all liabilities to the extent allowable by law. In 4.0, an interpretation clause was added to help ensure that the disclaimer would be interpreted as intended given variations in local law. Of course, licensors may continue to offer warranties and specialized disclaimers separately from the license.
Some ports of 3.0 include warranties where they may not be disclaimed under local law. You may compare how different jurisdictions implemented this section of the license.
Licensor expressly waives rights to enforce, and grants permission to circumvent, technological protection measures
Version 4.0 includes an explicit waiver of, or agreement not to assert, any right licensor may otherwise have to enforce anti-circumvention of any effective technological measures applied to licensed material. CC licensors may apply such measures to their own licensed material, but the 4.0 licenses ensure that, to the extent possible, users are able to exercise the licensed rights when applied by or with the permission of the licensor. To reinforce this, the version 4.0 licenses also expressly grant permission to circumvent those measures.
It is always possible for a licensor to upload his or her own work to a platform that applies technological protection measures, even though the licensor chooses to use a CC license. The permission for a third-party platform to apply ETMs is separate from the CC license, and the CC license cannot restrict that additional permission because CC licenses are nonexclusive. In many jurisdictions, that third party may be able to enforce ETMs through civil or criminal anti-circumvention laws even though the licensor has waived or agreed not to assert any such right under the CC license. Licensees should make themselves aware of any legal limits on their ability to circumvent ETMs in advance of doing so.
In versions 1.0, 2.0, 2.5, and 3.0, the waiver of any right to enforce and the permission to circumvent are not express; however, this does not preclude any implied right to do so that may exist.
Automatic restoration of rights after termination if license violations corrected
In version 4.0, licensees may regain their rights to use licensed material after the license terminates by correcting a license violation within 30 days of discovering it.
In all license versions, a breach of the license terms results in automatic termination. Under versions 1.0, 2.0, 2.5, and 3.0, express permission from the licensor is required for licensees to regain their rights to use the work. In version 4.0, a new provision allows the rights to be automatically reinstated without express permission from the licensor, provided that the violation is corrected within 30 days of its discovery. This is similar to provisions in a handful of other public licenses.
In all versions, a licensor may of course reinstate permissions at any time.
Collecting societies regimes addressed
Under 4.0, licensors waive any right to collect royalties under collecting society schemes if they have chosen licenses permitting commercial uses. A licensor may collect royalties for commercial uses for works under the NonCommercial licenses.
Many users of Creative Commons licenses are members of collective rights societies like ASCAP, BMI, BUMA/STEMRA, and others that manage copyright on behalf of owners. Every license version from the 2.0 suite onward contains clauses that account for the existence of those arrangements. They provide, for instance, that for works offered under a NonCommercial license, the licensor retains the right to collect royalties for commercial uses of the work. The structure of the provisions in the 2.0 and 2.5 licenses differs from that in the version 3.0 and 4.0 licenses. The 2.x licenses specifically regulate music, sound recordings, and webcasting. As those licenses were ported to different jurisdictions, those provisions were adjusted to conform to the local collecting society situation.
The version 3.0 licenses and later employ a broad, harmonized strategy to collective rights societies. This strategy still allows jurisdictions to adopt an approach that best aligns with local law and society structure in the 3.0 licenses, but also ensures that the approach is implemented consistently across jurisdictions. In the international license, as regards compulsory royalty collection, the licensor reserves any right they have to collect those royalties in jurisdictions in which collection cannot be waived. In those jurisdictions in which compulsory royalty collection can be waived, the right to collect royalties is waived completely for those licenses that permit commercial use, and is reserved for commercial uses in those licenses that permit NonCommercial use only. For voluntary royalty schema, the licensor reserves the right to collect royalties for commercial uses in those licenses that permit NonCommercial use only, and waives the right to collect such royalties for licenses permitting commercial use. This clause covers both individual royalty collection and, in the event that the licensor is a member of a collecting society that collects such royalties, collection via such societies to the extent permitted by law. Some ports of the version 3.0 licenses include only those clauses that address the particular situation in the jurisdiction. Others have adopted all the language from the international license in hopes of international harmonization, or out of concern that their jurisdiction’s regime may change. You may compare how different jurisdictions implemented this section of the license.
Compatibility mechanism in BY-SA licenses
Under the 4.0 licenses, licensees may use licenses designated by CC as compatible for their contributions to adapted material.
The ShareAlike licenses require that licensees make their contributions to adapted material available under the same terms and conditions, or, where the license allows, under a license designated by CC as compatible. The version 1.0 ShareAlike licenses require that adaptations be made under exactly the same license as applied to the original work. Starting with the release of the 2.x license suites, CC expanded compatibility by allowing contributions to adapted material to be created under the same or later version of the original license, including other ported versions of the same or later version of the license. The 3.0 Attribution-ShareAlike goes one step further, by allowing those contributions to be licensed under under a “Creative Commons Compatible License,” defined to mean licenses approved by CC as essentially equivalent to the 3.0 Attribution-ShareAlike license.
To date, CC has not approved any other licenses as compatible. However, CC will develop a compatibility process shortly following launch of the 4.0 licenses, and begin evaluating other licenses. You can view the list of compatible licenses, and a post about the upcoming compatibility process. You may also want to review CC’s statement of intent for the Attribution-ShareAlike licenses, and a draft statement that sets out further principles for the ShareAlike licenses.
Compatibility mechanism in BY-NC-SA licenses
In the 4.0 licenses, the same compatibility mechanism is present in the BY-NC-SA license as in BY-SA. Adapted material may be licensed under BY-NC-SA, version 4.0 or later, or any license CC has designated as compatible. To date, CC has not identified any other licenses as compatible; the process and criteria will be maintained on the compatibility page. There is no compatibility mechanism in the 1.0, 2.0, 2.5, or 3.0 versions of BY-NC-SA.
Adapted material usable under conditions of adapter's license
In version 4.0, CC added a provision in the ShareAlike licenses that enables downstream licensees to refer only to the adapter’s license when using adapted material that contains the copyrightable contributions of multiple authors. This feature is designed to minimize complexity for reusers where they are using a later version of the ShareAlike license or a compatible license as their adapter's license. In 4.0, users need only refer to a single set of conditions contained in the last license applied to reuse adapted material, rather than parsing the conditions of the original and other adapter's licenses (to the extent the licenses differ).
In all cases, the licenses stack (the later license does not supplant all previously-applied licenses) when adapted material is created. In particular, the license originally applied to the material being remixed continues to apply once remixed, however permission is given in 4.0 for licensees to meet the conditions of the 4.0 license with reference to those in the adapter's license.
Prior to the 4.0 versioning process, CC had not always been clear that the ShareAlike licenses stacked just as they stack for the BY and BY-NC licenses, and reasonable minds do differ on this point. CC believes, however, that this is the best reading of its all of its licenses that permit adaptations prior to 4.0 and, now, has made that explicit in version 4.0.
In Version 4.0, licensees are granted permission to create adaptations of material licensed under one of the NoDerivatives licenses, but not permission to share the adaptations publicly.
In general, private personal use does not require the permission of the licensor and, therefore, does not require that the conditions of the CC license be followed. In 4.0, NoDerivatives is a partial rather than an absolute limitation on the rights granted. It does not restrict the production of adaptations (an exclusive right of creators under copyright), but it does prohibit the public sharing of those adaptations (also an exclusive right of creators under copyright). This change enables private activities that may result in the creation of adaptations whether intentionally or unintentionally, such as adaptations made in the course or as a result of text and data mining.
The creation of adaptations in connection with those and other activities are not permitted under the 3.0 and earlier versions absent an applicable exception or limitation.
Features remaining unchanged across license versions
All of the CC licenses require attribution where "BY" is a license element, which is all but five of the eleven version 1.0 licenses.The required mode of attribution differs slightly among the versions, and is progressively more flexible with each version. The version 1.0 suite is unique because it contains five CC licenses that do not require attribution. All subsequent license suites make attribution a standard requirement, though the licensor may request removal in certain circumstances. It is also possible under all license versions for a licensor to release works anonymously, and to waive the requirement by not providing authorship information. Where an element of attribution information is not provided by the licensor, the licensee is not required to provide it.
Definition of "NonCommercial"
While the Creative Commons licenses have evolved over time, the scope of permitted uses under the NonCommercial licenses has remained unchanged across all license suites. (In 4.0, there was a small adjustment to the wording of the definition which was not intended to change its scope.) The NonCommercial clause prohibits the exercise of rights granted under the NonCommercial licenses “in any manner that is primarily intended for or directed toward commercial advantage or monetary compensation.” In 2008, Creative Commons conducted a study on the meaning of NonCommercial in the online environment.
During the 4.0 process, CC took another look at the role of these licenses in general as well as the NonCommercial definition, and considered a name change to "Commercial Rights Reserved". The ultimate decision was to leave unchanged the license name and definition.
Application of effective technological measures by users of CC-licensed works prohibited
All CC license versions prohibit licensees (as opposed to licensors) from using effective technological measures such as “digital rights management” software to restrict the ability of those who receive a CC-licensed work to exercise rights granted under the license. To be clear, encryption or an access limitation is not necessarily a technical protection measure prohibited by the licenses. For example, content sent via email and encrypted with the recipient's public key does not restrict use of the work by the recipient. Likewise, limiting recipients to a set of users (e.g., with a username and password) does not restrict use of the work by the recipients. In the cases above, encryption or an access limitation does not violate the prohibition on technological measures because the recipient is not prevented from exercising all rights granted by the license (including rights of further redistribution).
This treatment was re-evaluated during the public process leading to release of the version 3.0 license suite. CC considered arguments in favor of such measures, coupled with an obligation of parallel distribution; these arguments were also reconsidered during the 4.0 process. However, in both versioning processes, those arguments were ultimately rejected.
Note that in 4.0, CC introduced a definition of Effective Technological Measures. This definition is not intended to change the scope of what is and is not allowed, but instead provide long-needed clarification over the scope of the prohibition.
Exceptions and limitations unaffected
All CC licenses only govern uses that would otherwise be restricted by copyright and other closely related rights as provided in the licenses. If a use is not regulated by virtue of an applicable exception or limitation, the license does not apply and there is no need to follow the license conditions. The licenses do not create obligations where they would not otherwise exist.
Effective for all copyrightable material
All Creative Commons license versions may be used with all copyrightable works (though CC recommends against using its licenses for computer software). Such works include compilations of data that exhibit the requisite level of creativity for copyright protection under applicable law. Thus, to the extent compilations of data are protected by copyright, Creative Commons licenses are suitable licenses for granting permission to exercise that right. For the avoidance of doubt, version 3.0 and 4.0 licenses explicitly identify compilations as material that may be licensed.
Notice of warranty disclaimers must be retained
The CC licenses all require users to retain notices of disclaimers of warranties if supplied with the licensed material. Customized disclaimers never form part of the Creative Commons license, but may be offered.
Synching creates adaptations
In all license versions, synching CC-licensed audio in timed relation with a video to create an audiovisual work creates an adaptation of that audio work for purposes of the license, regardless of whether the new work would be considered an adaptation under the relevant copyright law. This means, for example, that the requirements of ShareAlike are triggered if the audio work is licensed under a ShareAlike license, and that such works may be made but not shared if licensed under a NoDerivatives license as of version 4.0.
None of the Creative Commons licenses grant permission to sublicense the licensed material. All of the licenses are direct licenses from the original licensor to all recipients. All permissions granted come directly from the original licensor, creating a direct relationship for enforcement and other purposes between the original licensor and all recipients.
Licensing of collections
Including a CC-licensed work in a collection (a work comprised of separate and independent works) is permitted by all CC licenses. However the collective work as a whole is licensed, the license on the collection does not affect the CC license applied to the work.
In 4.0, reference to distribution in a collection was removed from the license as unnecessary. There is no change from previous versions, however.
Licensing of contributions to BY and BY-NC adaptations
The 4.0 licenses make clear for the first time how contributions to adaptations of BY and BY-NC works may be licensed. Specifically, an adapting licensee may apply any license to her contributions provided that license does not prevent users of the adaption from complying with the original license. While new in 4.0, the introduction of this provision is intended as a clarifier only and is not a change from how earlier versions operate.
Links to the International (unported) legal code for the six licenses making up the current suite, for each version: