ICU-22922 ICU 77rc download page

docs/download/77.md

@@ -16,24 +16,22 @@ License & terms of use: http://www.unicode.org/copyright.html
 ICU is the [premier library for software internationalization](https://icu.unicode.org/#h.i33fakvpjb7o),
 used by a [wide array of companies and organizations](https://icu.unicode.org/#h.f9qwubthqabj).
 
-## Not released yet!
+## Release Candidate
 
-**ICU 77 is still under development.
-Once we have a release candidate, use it for testing, but do not use it in production!**
+**Please use this release candidate for testing, but do not use it in production!**
 
 ## Release Overview
 
-* TODO -- below is old
-
 ICU 77 updates to
 [CLDR 47](https://cldr.unicode.org/downloads/cldr-47)
-(TODO: blog)
+([alpha blog](https://blog.unicode.org/2025/02/unicode-cldr-47-alpha-now-available-for.html))
 locale data with new locales, and various additions and corrections.
 
-TODO: Highlights
+ICU 77 is mostly focused on bug fixes, segmentation conformance, and other refinements.
 
-The Java technology preview implementation of the CLDR MessageFormat 2.0 specification has been updated to match the
-[CLDR 46.1 spec](https://www.unicode.org/reports/tr35/tr35-74/tr35-messageFormat.html).
+The Java technology preview implementation of the CLDR MessageFormat 2.0 specification has been updated to incorporate the
+[CLDR 46.1 spec](https://www.unicode.org/reports/tr35/tr35-74/tr35-messageFormat.html)
+plus most but not all of the CLDR 47 changes.
 
 The C++ technology preview implementation of MessageFormat 2.0 is not yet quite up to date with CLDR 46.1.
 
@@ -55,7 +53,7 @@ Note: There may be additional commits on the [maint/maint-77](https://github.com
 ## Common Changes
 
 * [CLDR 47](https://cldr.unicode.org/downloads/cldr-47)
-  (TODO: blog):
+  ([alpha blog](https://blog.unicode.org/2025/02/unicode-cldr-47-alpha-now-available-for.html)):
   * No major data collection for existing locales; focus on bug fixes and structural improvements
   * New regional variants: English in several European countries, and Cantonese in Macau (`yue_Hant_MO`)
   * Improved RBNF (number spellout) and transliteration data
@@ -84,65 +82,17 @@ Note: There may be additional commits on the [maint/maint-77](https://github.com
 ## ICU4J Specific Changes
 
 * [API Changes since ICU4J 76](https://htmlpreview.github.io/?https://github.com/unicode-org/icu/blob/maint/maint-77/icu4j/APIChangeReport.html)
-* The Java technology preview implementation of the CLDR MessageFormat 2.0 specification has been updated to match the
-  [CLDR 46.1 spec](https://www.unicode.org/reports/tr35/tr35-74/tr35-messageFormat.html).
+* The Java technology preview implementation of the CLDR MessageFormat 2.0 specification has been updated to incorporate the
+  [CLDR 46.1 spec](https://www.unicode.org/reports/tr35/tr35-74/tr35-messageFormat.html)
+  plus most but not all of the CLDR 47 changes.
 
 ## Known Issues
 
-* TODO -- below is old
-* One late CLDR 46 bug fix was accidentally omitted from ICU 46:
-  [CLDR-18002](https://unicode-org.atlassian.net/browse/CLDR-18002) Fix likely subtag inconsistency
-  ([CLDR PR #4105](https://github.com/unicode-org/cldr/pull/4105))
+* (none yet)
 
 ## Migration Issues
 
-* TODO -- below is old
-
-### C++ Header-Only APIs
-ICU 76 is the first version where we add what we call C++ header-only APIs.
-These are especially intended for users who rely on only binary stable DLL/library exports of C APIs
-(C++ APIs cannot be binary stable).
-
-_Please test these new APIs and let us know if you find problems —
-especially if you find a platform/compiler/options combination
-where the call site does end up calling into ICU DLL/library exports._
-
-Remember that regular C++ APIs can be hidden by callers defining `U_SHOW_CPLUSPLUS_API=0`.
-The new header-only APIs can be separately enabled via `U_SHOW_CPLUSPLUS_HEADER_API=1`.
-
-([GitHub query for `U_SHOW_CPLUSPLUS_HEADER_API` in public header files](https://github.com/search?q=repo%3Aunicode-org%2Ficu+U_SHOW_CPLUSPLUS_HEADER_API+path%3Aunicode%2F*.h&type=code))
-
-These are C++ definitions that are not exported by the ICU DLLs/libraries,
-are thus inlined into the calling code,
-and which may call ICU C APIs but not into ICU non-header-only C++ APIs.
-
-The header-only APIs are defined in a nested `header` namespace.
-If entry point renaming is turned off (the main namespace is `icu` rather than `icu_76` etc.),
-then the new `U_HEADER_ONLY_NAMESPACE` is `icu::header`.
-
-([Link to the API proposal which introduced this concept](https://docs.google.com/document/d/1xERVccTYsptzjfbjcj6HDtoKVF_mEKmslPsOiQzzaFg/view#heading=h.cf4bmhjgozry))
-
-For example, for iterating over the code point ranges in a `USet` (excluding the strings):
-
-```c++
-U_NAMESPACE_USE
-using U_HEADER_NESTED_NAMESPACE::USetRanges;
-LocalUSetPointer uset(uset_openPattern(u"[abcçカ🚴]", -1, &errorCode));
-for (auto [start, end] : USetRanges(uset.getAlias())) {
-    printf("uset.range U+%04lx..U+%04lx\n", (long)start, (long)end);
-}
-for (auto range : USetRanges(uset.getAlias())) {
-    for (UChar32 c : range) {
-        printf("uset.range.c U+%04lx\n", (long)c);
-    }
-}
-```
-
-(Implementation note: On most platforms, when compiling ICU itself,
-the `U_HEADER_ONLY_NAMESPACE` is `icu::internal`,
-so that any such symbols that get exported differ from the ones that calling code sees.
-On Windows, where DLL exports are explicit,
-the namespace is always the same, but these header-only APIs are not marked for export.)
+* (none yet)
 
 ### Migration Issues Related to CLDR
 * See [CLDR 47 migration issues](https://cldr.unicode.org/downloads/cldr-47#migration)
@@ -174,7 +124,7 @@ ICU locale data was generated from CLDR data equivalent to:
 * <https://github.com/unicode-org/cldr/releases/tag/release-47-alpha2>
 * <https://github.com/unicode-org/cldr-staging/releases/tag/release-47-alpha2>
 
-[Maven dependency](https://central.sonatype.com/artifact/com.ibm.icu/icu4j):
+TODO: [Maven dependency](https://central.sonatype.com/artifact/com.ibm.icu/icu4j):
 ```
 <dependency>
   <groupId>com.ibm.icu</groupId>