remove mentions of legacy CDTs & cos6 from README

README.md

@@ -14,7 +14,7 @@ The following options are available when adding a CDT in the configuration file:
 
  - `custom` (boolean): Set to `true` to declare the CDT as a custom CDT. This will
    cause the CDT generation code to remove any instance of the CDT that appears in the
-   `cdts` or `legacy_cdts` directories.
+   `cdts` directory.
  - `license_file` (str or list of str or null): Sets the license file for a CDT. If set to
    a string or a list of strings giving the paths to the files, it will copy the licenses
    to the recipe and modify the recipe `meta.yaml` appropriately. If set to `null`, it will
@@ -64,37 +64,24 @@ If you have a CDT recipe that is not autogenerated, it can be added as follows.
 
 1. Add the CDT name to the `cdt_slugs.yaml` file. Make sure to set `custom: true`
    in the metadata in the file.
-2. Add the CDT recipe in a directory under the full CDT package name in either
-   the `custom_cdts` or `legacy_custom_cdts` folder depending on whether or not
-   the CDT is targeted at the old-style CDT format or the new-style one. If you
-   do not know, ask someone on `conda-forge/core`.
+2. Add the CDT recipe in a directory under the full CDT package name in the
+   `custom_cdts` folder. If you do not know, ask someone on `conda-forge/core`.
 3. Commit any changes from steps 1+2 and open the PR.
 
 The CI service will build the CDTs, report any errors, etc.
 
 
-## Old-style/legacy vs. New-style CDTs
+## CDTs constraints
 
-The old-style CDTs are targeted at the conda-forge compilers that do not use the
-`sysroot_{conda subdir}` packages (e.g., `sysroot_linux-64`, `sysroot_linux-aarch64`, etc.)
-and build their own copy of glibc. These compilers also have `cos6` or `cos7`
-in the name of the sysroot directory. The new-style CDTs use a sysroot directory
-without `cos6` or `cos7` and are meant to work with the new conda-forge
-compilers that depend on the `sysroot_{conda subdir}` packages.
+CDTs are meant to work with conda-forge compilers that depend on the
+`sysroot_{conda subdir}` packages.
 
-**old-style CDT specs**
-- needs to have `no_hoist` in the source sections
-- sysroot directory has `conda_cos6` or `conda_cos7` in the path
-- needs to have `run_constrained` entry of `sysroot_{conda subdir} ==99999999999` to prevent
-  it from being co-installed w/ the new compilers or CDTs
-
-**new-style CDT specs**
 - needs to have `no_hoist` in the source sections
 - sysroot directory has `conda` only in the path
 - needs to have a `run` requirement on the proper version of the
   `sysroot_{subdir}` package so that it is only installed with CDTs from the
   right version of CentOS
-- the versions of `sysroot_{conda subdir}` are 2.12 for CentOS 6 and 2.17 for CentOS 7.
+- the versions of `sysroot_{conda subdir}` are 2.17 for CentOS 7 and 2.28 for Alma 8
 
 ## Azure CI Setup
 

README.md.tmpl

@@ -14,7 +14,7 @@ The following options are available when adding a CDT in the configuration file:
 
  - `custom` (boolean): Set to `true` to declare the CDT as a custom CDT. This will
    cause the CDT generation code to remove any instance of the CDT that appears in the
-   `cdts` or `legacy_cdts` directories.
+   `cdts` directory.
  - `license_file` (str or list of str or null): Sets the license file for a CDT. If set to
    a string or a list of strings giving the paths to the files, it will copy the licenses
    to the recipe and modify the recipe `meta.yaml` appropriately. If set to `null`, it will
@@ -64,37 +64,24 @@ If you have a CDT recipe that is not autogenerated, it can be added as follows.
 
 1. Add the CDT name to the `cdt_slugs.yaml` file. Make sure to set `custom: true`
    in the metadata in the file.
-2. Add the CDT recipe in a directory under the full CDT package name in either
-   the `custom_cdts` or `legacy_custom_cdts` folder depending on whether or not
-   the CDT is targeted at the old-style CDT format or the new-style one. If you
-   do not know, ask someone on `conda-forge/core`.
+2. Add the CDT recipe in a directory under the full CDT package name in the
+   `custom_cdts` folder. If you do not know, ask someone on `conda-forge/core`.
 3. Commit any changes from steps 1+2 and open the PR.
 
 The CI service will build the CDTs, report any errors, etc.
 
 
-## Old-style/legacy vs. New-style CDTs
+## CDTs constraints
 
-The old-style CDTs are targeted at the conda-forge compilers that do not use the
-`sysroot_{conda subdir}` packages (e.g., `sysroot_linux-64`, `sysroot_linux-aarch64`, etc.)
-and build their own copy of glibc. These compilers also have `cos6` or `cos7`
-in the name of the sysroot directory. The new-style CDTs use a sysroot directory
-without `cos6` or `cos7` and are meant to work with the new conda-forge
-compilers that depend on the `sysroot_{conda subdir}` packages.
+CDTs are meant to work with conda-forge compilers that depend on the
+`sysroot_{conda subdir}` packages.
 
-**old-style CDT specs**
-- needs to have `no_hoist` in the source sections
-- sysroot directory has `conda_cos6` or `conda_cos7` in the path
-- needs to have `run_constrained` entry of `sysroot_{conda subdir} ==99999999999` to prevent
-  it from being co-installed w/ the new compilers or CDTs
-
-**new-style CDT specs**
 - needs to have `no_hoist` in the source sections
 - sysroot directory has `conda` only in the path
 - needs to have a `run` requirement on the proper version of the
   `sysroot_{subdir}` package so that it is only installed with CDTs from the
   right version of CentOS
-- the versions of `sysroot_{conda subdir}` are 2.12 for CentOS 6 and 2.17 for CentOS 7.
+- the versions of `sysroot_{conda subdir}` are 2.17 for CentOS 7 and 2.28 for Alma 8
 
 ## Azure CI Setup