add news to warn about upcoming default change

news/4890-package-format-cli-options

@@ -1,6 +1,22 @@
 ### Enhancements
 
 * `--package-format` introduced as command line argument. (#4890 via #5209)
-  * This takes precedence over default value and .condarc
-  * Normalization occurs so 1,tar.bz2,.tar.bz2,2,conda,.conda are all recognized and mapped appropriately
-  * Other options are rejected
+  * This takes precedence over default value and `condarc`.
+  * Normalization occurs so `1`, `"1"`, `tar.bz2`,`.tar.bz2`, `2`, `"2"`, `conda`, `.conda` are all recognized and mapped appropriately.
+  * Other options are rejected.
+
+### Bug fixes
+
+* <news item>
+
+### Deprecations
+
+* <news item>
+
+### Docs
+
+* <news item>
+
+### Other
+
+* <news item>

news/5534-warn-default-conda-pkg-format

@@ -0,0 +1,19 @@
+### Enhancements
+
+* <news item>
+
+### Bug fixes
+
+* <news item>
+
+### Deprecations
+
+* The default value for `--package-format` and `conda_pkg_format` will become `.conda` in 25.1. (#5534)
+
+### Docs
+
+* <news item>
+
+### Other
+
+* <news item>