contributor/versioning.md - accumulo-website - Git at Google

 ---
 title: Versioning
 redirect_from: /versioning
 ---

 ## Long Term Maintenance (LTM)
 {: #LTM }

 The Apache Accumulo PMC has adopted a Long Term Maintenance (LTM) release strategy.

 ### LTM Versions:

 1. Periodically release a new LTM `major.minor.0` version (approximately every 2 years),
 2. Maintain the LTM releases with `major.minor.(patch++)` releases until 1 year after the next LTM,
 3. Support upgrades from both the immediately preceding LTM and non-LTM versions

 This strategy implies that no more than one or two LTM releases will be
 actively maintained at any given time, with one year of overlap.

 ### Non-LTM versions:

 1. Release intermediate non-LTM `major.minor.0` versions that are not expected to receive patch/bugfix releases,
 2. Roll patches/bugfixes targeting non-LTM versions into the next `major.minor.0` release

 ### Goals of the LTM strategy:
 - Streamline maintaining multiple versions of Accumulo
 - Encourage development on newer versions
 - Provide greater confidence for users to upgrade and receive updates (within one year)
 - Help reduce the amount of work done by limiting upgrade paths

 Note: the above strategy is a declaration of **intent** only. We use the term
 "Long Term Maintenance" rather than the more familiar "Long Term Support" or
 "Long Term Stable" terms to avoid any implication of warranties
 from the use of the words "support" or "stable". See the project LICENSE for a full
 disclaimer of warranties. If you have questions, about this, please [contact] us.

 ## SemVer 2.0.0
 {: semver }

 The Apache Accumulo PMC closed a vote on 2014/12/12 which adopted [Semantic Versioning 2.0.0][semver] as
 the reference document on the meaning and requirements of the versions of Apache Accumulo. Semantic
 versioning requires a definition of a public API: this definition is unchanged over previous releases and
 can be found in section 9 of the [README][readme]. A copy of the specification is included here, licensed under
 [Creative Commons - CC BY 3.0][cc]:

 ### Semantic Versioning Specification (SemVer)

 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL"
 in this document are to be interpreted as described in RFC 2119.

 1. Software using Semantic Versioning MUST declare a public API. This API could be declared in the code itself or exist
 strictly in documentation. However it is done, it should be precise and comprehensive.

 2. A normal version number MUST take the form X.Y.Z where X, Y, and Z are non-negative integers, and MUST NOT contain
 leading zeroes. X is the major version, Y is the minor version, and Z is the patch version. Each element MUST increase
 numerically. For instance: 1.9.0 -> 1.10.0 -> 1.11.0.

 3. Once a versioned package has been released, the contents of that version MUST NOT be modified. Any modifications MUST
 be released as a new version.

 4. Major version zero (0.y.z) is for initial development. Anything may change at any time. The public API should not be
 considered stable.

 5. Version 1.0.0 defines the public API. The way in which the version number is incremented after this release is dependent
 on this public API and how it changes.

 6. Patch version Z (x.y.Z | x > 0) MUST be incremented if only backwards compatible bug fixes are introduced. A bug fix
 is defined as an internal change that fixes incorrect behavior.

 7. Minor version Y (x.Y.z | x > 0) MUST be incremented if new, backwards compatible functionality is introduced to the
 public API. It MUST be incremented if any public API functionality is marked as deprecated. It MAY be incremented if
 substantial new functionality or improvements are introduced within the private code. It MAY include patch level changes.
 Patch version MUST be reset to 0 when minor version is incremented.

 8. Major version X (X.y.z | X > 0) MUST be incremented if any backwards incompatible changes are introduced to the public
 API. It MAY include minor and patch level changes. Patch and minor version MUST be reset to 0 when major version is incremented.

 9. A pre-release version MAY be denoted by appending a hyphen and a series of dot separated identifiers immediately following
 the patch version. Identifiers MUST comprise only ASCII alphanumerics and hyphen [0-9A-Za-z-]. Identifiers MUST NOT be empty.
 Numeric identifiers MUST NOT include leading zeroes. Pre-release versions have a lower precedence than the associated normal
 version. A pre-release version indicates that the version is unstable and might not satisfy the intended compatibility requirements
 as denoted by its associated normal version. Examples: 1.0.0-alpha, 1.0.0-alpha.1, 1.0.0-0.3.7, 1.0.0-x.7.z.92.

 10. Build metadata MAY be denoted by appending a plus sign and a series of dot separated identifiers immediately following
 the patch or pre-release version. Identifiers MUST comprise only ASCII alphanumerics and hyphen [0-9A-Za-z-]. Identifiers MUST
 NOT be empty. Build metadata SHOULD be ignored when determining version precedence. Thus two versions that differ only in the
 build metadata, have the same precedence. Examples: 1.0.0-alpha+001, 1.0.0+20130313144700, 1.0.0-beta+exp.sha.5114f85.

 11. Precedence refers to how versions are compared to each other when ordered. Precedence MUST be calculated by separating
 the version into major, minor, patch and pre-release identifiers in that order (Build metadata does not figure into precedence).
 Precedence is determined by the first difference when comparing each of these identifiers from left to right as follows: Major,
 minor, and patch versions are always compared numerically. Example: 1.0.0 < 2.0.0 < 2.1.0 < 2.1.1. When major, minor, and patch
 are equal, a pre-release version has lower precedence than a normal version. Example: 1.0.0-alpha < 1.0.0. Precedence for two
 pre-release versions with the same major, minor, and patch version MUST be determined by comparing each dot separated identifier
 from left to right until a difference is found as follows: identifiers consisting of only digits are compared numerically and
 identifiers with letters or hyphens are compared lexically in ASCII sort order. Numeric identifiers always have lower precedence
 than non-numeric identifiers. A larger set of pre-release fields has a higher precedence than a smaller set, if all of the
 preceding identifiers are equal. Example: 1.0.0-alpha < 1.0.0-alpha.1 < 1.0.0-alpha.beta < 1.0.0-beta < 1.0.0-beta.2 <
 1.0.0-beta.11 < 1.0.0-rc.1 < 1.0.0.


 [semver]: https://semver.org/spec/v2.0.0
 [readme]: https://gitbox.apache.org/repos/asf?p=accumulo.git;a=blob;f=README.md;hb=refs/heads/main
 [cc]: https://creativecommons.org/licenses/by/3.0
 [contact]: {{ site.baseurl }}/contact-us
	---
	title: Versioning
	redirect_from: /versioning
	---

	## Long Term Maintenance (LTM)
	{: #LTM }

	The Apache Accumulo PMC has adopted a Long Term Maintenance (LTM) release strategy.

	### LTM Versions:

	1. Periodically release a new LTM `major.minor.0` version (approximately every 2 years),
	2. Maintain the LTM releases with `major.minor.(patch++)` releases until 1 year after the next LTM,
	3. Support upgrades from both the immediately preceding LTM and non-LTM versions

	This strategy implies that no more than one or two LTM releases will be
	actively maintained at any given time, with one year of overlap.

	### Non-LTM versions:

	1. Release intermediate non-LTM `major.minor.0` versions that are not expected to receive patch/bugfix releases,
	2. Roll patches/bugfixes targeting non-LTM versions into the next `major.minor.0` release

	### Goals of the LTM strategy:
	- Streamline maintaining multiple versions of Accumulo
	- Encourage development on newer versions
	- Provide greater confidence for users to upgrade and receive updates (within one year)
	- Help reduce the amount of work done by limiting upgrade paths

	Note: the above strategy is a declaration of intent only. We use the term
	"Long Term Maintenance" rather than the more familiar "Long Term Support" or
	"Long Term Stable" terms to avoid any implication of warranties
	from the use of the words "support" or "stable". See the project LICENSE for a full
	disclaimer of warranties. If you have questions, about this, please [contact] us.

	## SemVer 2.0.0
	{: semver }

	The Apache Accumulo PMC closed a vote on 2014/12/12 which adopted [Semantic Versioning 2.0.0][semver] as
	the reference document on the meaning and requirements of the versions of Apache Accumulo. Semantic
	versioning requires a definition of a public API: this definition is unchanged over previous releases and
	can be found in section 9 of the [README][readme]. A copy of the specification is included here, licensed under
	[Creative Commons - CC BY 3.0][cc]:

	### Semantic Versioning Specification (SemVer)

	The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL"
	in this document are to be interpreted as described in RFC 2119.

	1. Software using Semantic Versioning MUST declare a public API. This API could be declared in the code itself or exist
	strictly in documentation. However it is done, it should be precise and comprehensive.

	2. A normal version number MUST take the form X.Y.Z where X, Y, and Z are non-negative integers, and MUST NOT contain
	leading zeroes. X is the major version, Y is the minor version, and Z is the patch version. Each element MUST increase
	numerically. For instance: 1.9.0 -> 1.10.0 -> 1.11.0.

	3. Once a versioned package has been released, the contents of that version MUST NOT be modified. Any modifications MUST
	be released as a new version.

	4. Major version zero (0.y.z) is for initial development. Anything may change at any time. The public API should not be
	considered stable.

	5. Version 1.0.0 defines the public API. The way in which the version number is incremented after this release is dependent
	on this public API and how it changes.

	6. Patch version Z (x.y.Z \| x > 0) MUST be incremented if only backwards compatible bug fixes are introduced. A bug fix
	is defined as an internal change that fixes incorrect behavior.

	7. Minor version Y (x.Y.z \| x > 0) MUST be incremented if new, backwards compatible functionality is introduced to the
	public API. It MUST be incremented if any public API functionality is marked as deprecated. It MAY be incremented if
	substantial new functionality or improvements are introduced within the private code. It MAY include patch level changes.
	Patch version MUST be reset to 0 when minor version is incremented.

	8. Major version X (X.y.z \| X > 0) MUST be incremented if any backwards incompatible changes are introduced to the public
	API. It MAY include minor and patch level changes. Patch and minor version MUST be reset to 0 when major version is incremented.

	9. A pre-release version MAY be denoted by appending a hyphen and a series of dot separated identifiers immediately following
	the patch version. Identifiers MUST comprise only ASCII alphanumerics and hyphen [0-9A-Za-z-]. Identifiers MUST NOT be empty.
	Numeric identifiers MUST NOT include leading zeroes. Pre-release versions have a lower precedence than the associated normal
	version. A pre-release version indicates that the version is unstable and might not satisfy the intended compatibility requirements
	as denoted by its associated normal version. Examples: 1.0.0-alpha, 1.0.0-alpha.1, 1.0.0-0.3.7, 1.0.0-x.7.z.92.

	10. Build metadata MAY be denoted by appending a plus sign and a series of dot separated identifiers immediately following
	the patch or pre-release version. Identifiers MUST comprise only ASCII alphanumerics and hyphen [0-9A-Za-z-]. Identifiers MUST
	NOT be empty. Build metadata SHOULD be ignored when determining version precedence. Thus two versions that differ only in the
	build metadata, have the same precedence. Examples: 1.0.0-alpha+001, 1.0.0+20130313144700, 1.0.0-beta+exp.sha.5114f85.

	11. Precedence refers to how versions are compared to each other when ordered. Precedence MUST be calculated by separating
	the version into major, minor, patch and pre-release identifiers in that order (Build metadata does not figure into precedence).
	Precedence is determined by the first difference when comparing each of these identifiers from left to right as follows: Major,
	minor, and patch versions are always compared numerically. Example: 1.0.0 < 2.0.0 < 2.1.0 < 2.1.1. When major, minor, and patch
	are equal, a pre-release version has lower precedence than a normal version. Example: 1.0.0-alpha < 1.0.0. Precedence for two
	pre-release versions with the same major, minor, and patch version MUST be determined by comparing each dot separated identifier
	from left to right until a difference is found as follows: identifiers consisting of only digits are compared numerically and
	identifiers with letters or hyphens are compared lexically in ASCII sort order. Numeric identifiers always have lower precedence
	than non-numeric identifiers. A larger set of pre-release fields has a higher precedence than a smaller set, if all of the
	preceding identifiers are equal. Example: 1.0.0-alpha < 1.0.0-alpha.1 < 1.0.0-alpha.beta < 1.0.0-beta < 1.0.0-beta.2 <
	1.0.0-beta.11 < 1.0.0-rc.1 < 1.0.0.


	[semver]: https://semver.org/spec/v2.0.0
	[readme]: https://gitbox.apache.org/repos/asf?p=accumulo.git;a=blob;f=README.md;hb=refs/heads/main
	[cc]: https://creativecommons.org/licenses/by/3.0
	[contact]: {{ site.baseurl }}/contact-us