Document Berkeley DB 4.8 wallet compatibility

INSTALL

@@ -17,9 +17,9 @@ For a manual build, build depends first and configure against its config.site:
     make
 
 The current native Qt wallet depends baseline includes Qt 6.8.3, OpenSSL 3.5.6,
-Boost 1.91.0, Expat 2.8.0, FreeType 2.13.3, protobuf, Berkeley DB, libevent,
-and GMP. Prefer the helper scripts in `contrib/` for repeatable fresh-host
-builds.
+Boost 1.91.0, Expat 2.8.0, FreeType 2.14.3, Berkeley DB 4.8.30, libevent, and
+GMP. Protobuf/BIP70 payment requests were removed. Prefer the helper scripts in
+`contrib/` for repeatable fresh-host builds.
 
 Always verify source checksums and release signatures when building a release.
 

README.md

@@ -36,8 +36,8 @@ sudo apt install -y mingw-w64
 
 The preferred build path uses the deterministic `depends/` system instead of
 mixing system libraries. The current native Ubuntu wallet path builds Qt 6.8.3,
-OpenSSL 3.5.6, Boost 1.91.0, Expat 2.8.0, FreeType 2.14.3, protobuf,
-Berkeley DB, and supporting libraries inside `depends/<host-triplet>/`.
+OpenSSL 3.5.6, Boost 1.91.0, Expat 2.8.0, FreeType 2.14.3, Berkeley DB
+4.8.30, and supporting libraries inside `depends/<host-triplet>/`.
 
 All dependency builds are executed from within the `depends/` directory or via
 the helper scripts in `contrib/`.

doc/dependencies.md

@@ -41,8 +41,10 @@ Modernization notes
 * Boost builds target Boost 1.91.0 through the deterministic depends path.
 * Protobuf was removed with obsolete BIP70 payment request support. Normal
   `agrarian:` URI payment handling remains available.
-* Berkeley DB remains 4.8.30 in depends for legacy wallet portability. Wallets
-  built against other BDB major versions may not be portable.
+* Berkeley DB intentionally remains 4.8.30 in depends for legacy `wallet.dat`
+  portability. Do not upgrade Berkeley DB in-place for normal releases; migrate
+  to a new wallet backend such as SQLite through a dedicated, tested wallet
+  migration path.
 
 Controlling dependencies
 ------------------------

doc/modernization.md

@@ -27,6 +27,10 @@ Obsolete BIP70 payment request support was removed to eliminate the protobuf
 and `protoc` dependency from the wallet build. Standard `agrarian:` URI payment
 links are still supported.
 
+Berkeley DB 4.8.30 is intentionally retained for legacy `wallet.dat`
+compatibility. Future wallet-storage modernization should add a dedicated SQLite
+backend and migration flow instead of changing the BDB version in-place.
+
 The currently verified binaries are:
 
 - Ubuntu daemon and command-line tools