Note exceptions to PSR freeze.

Author: Crell

bylaws/001-mission-and-structure.md

@@ -127,6 +127,6 @@ The Secretaries will ensure that the Maintainer has the necessary access and res
 
 The PHP FIG produces three primary forms of output artifact that are subject to established workflow processes.  This list is not exhaustive of the activity or publication that the PHP FIG may engage in.
 
-* A PHP Standard Recommendation (PSR) defines an interoperability standard that establishes a "contract" between providers and consumers.  The goal of any PSR is to encourage or facilitate cross-project collaboration and standardization.  PSRs are developed to a particular end-state and, once approved, are considered frozen in time to provide a stable and reliable target for implementers.  PSRs are developed by a Working Group.
+* A PHP Standard Recommendation (PSR) defines an interoperability standard that establishes a "contract" between providers and consumers.  The goal of any PSR is to encourage or facilitate cross-project collaboration and standardization.  PSRs are developed to a particular end-state and, once approved, are considered frozen in time to provide a stable and reliable target for implementers, with certain exceptions as specified in the PSR Amendments and PSR Evolution bylaws.  PSRs are developed by a Working Group.
 * A PHP Evolving Recommendation (PER) is a formal definition of best practices, references, guidelines, universal tooling, or tools to support the same.  They may evolve over time as the PHP language and ecosystem evolves.  PERs are developed by a Working Group.
 * Auxiliary Resources (ARs) are additional tools, code libraries, or examples that relate to or support a PSR or PER.  Examples include common partial implementations of a PSR or PER, "no-op" implementations, or testing utilities for PSR or PER implementations.  All ARs must directly relate to one or more PSRs or PERs.  An AR is developed by a Maintainer.