diff -up thunderbird-102.4.0/comm/third_party/rnp/moz.build.rnp-openssl thunderbird-102.4.0/comm/third_party/rnp/moz.build
--- thunderbird-102.4.0/comm/third_party/rnp/moz.build.rnp-openssl	2022-11-01 14:36:02.940726858 +0100
+++ thunderbird-102.4.0/comm/third_party/rnp/moz.build	2022-11-01 14:36:23.091726917 +0100
@@ -39,7 +39,7 @@ if CONFIG["CC_TYPE"] == "clang-cl":
 rnp_defines = {
     "HAVE_BZLIB_H": True,
     "HAVE_ZLIB_H": True,
-    "CRYPTO_BACKEND_BOTAN": True,
+    "CRYPTO_BACKEND_OPENSSL": True,
     "ENABLE_AEAD": True,
     "ENABLE_TWOFISH": True,
     "ENABLE_BRAINPOOL": True,