Clarify whether core packages are required to make bug-fix releases (#297)

---------

Co-authored-by: Stefan van der Walt <sjvdwalt@gmail.com>
Co-authored-by: M Bussonnier <bussonniermatthias@gmail.com>
Co-authored-by: Brigitta Sipőcz <b.sipocz@gmail.com>

Author: 4 people

spec-0000/index.md

@@ -1,5 +1,5 @@
 ---
-title: "SPEC 0 — Minimum Supported Versions"
+title: "SPEC 0 — Minimum Supported Dependencies"
 date: 2020-12-17
 author:
   - "Andreas C. Mueller <andreas.mueller.ml@gmail.com>"
@@ -24,7 +24,7 @@ endorsed-by:
 
 ## Description
 
-This SPEC recommends that all projects across the Scientific Python ecosystem adopt a common time-based policy for dropping support of older Python and core package versions.
+This SPEC recommends that all projects across the Scientific Python ecosystem adopt a common time-based policy for dropping dependencies. From the perspective of this SPEC, the dependencies in question are core packages as well as older Python versions.
 
 All versions refer to feature releases (i.e., Python 3.8.0, NumPy 1.19.0; not Python 3.8.1, NumPy 1.19.2).
 
@@ -33,12 +33,23 @@ Specifically, we recommend that:
 1. Support for Python versions be dropped **3 years** after their initial release.
 2. Support for core package dependencies be dropped **2 years** after their initial release.
 
+{{< admonition note >}}
+Core packages may or may not decide to provide bug fix releases during the full 2 year period after release.
+Therefore, projects may occasionally want to drop support for core package dependencies earlier than recommended by this SPEC.
+For instance, if a newer minimum version of a core package is needed by a project due to a critical bug fix,
+which is not backported to older versions.
+{{< /admonition >}}
+
 ### Core Project Endorsement
 
 <!--
 Briefly discuss what it means for a core project to endorse this SPEC.
 -->
 
+Core project endorsing this SPEC means that those projects encourage all projects across the Scientific Python ecosystem
+to limit how long they support older Python versions and older dependency versions.
+A core project endorsing this SPEC does **not** imply that that project will provide bug-fix releases for two full years after a release.
+
 ### Ecosystem Adoption
 
 <!--