diff --git a/Cargo.lock b/Cargo.lock
index a1210b2f38..d8b198b230 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -44,7 +44,7 @@ dependencies = [
  "actix-rt",
  "actix-service",
  "actix-utils",
- "base64",
+ "base64 0.22.1",
  "bitflags 2.9.3",
  "brotli",
  "bytes",
@@ -93,7 +93,7 @@ dependencies = [
  "cfg-if",
  "http 0.2.12",
  "regex-lite",
- "serde 1.0.219",
+ "serde",
  "tracing",
 ]
 
@@ -176,7 +176,7 @@ dependencies = [
  "once_cell",
  "pin-project-lite",
  "regex-lite",
- "serde 1.0.219",
+ "serde",
  "serde_json",
  "serde_urlencoded",
  "smallvec",
@@ -324,10 +324,10 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "69f7f8c3906b62b754cd5326047894316021dcfe5a194c8ea52bdd94934a3457"
 
 [[package]]
-name = "arrayvec"
-version = "0.5.2"
+name = "arraydeque"
+version = "0.5.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "23b62fc65de8e4e7f52534fb52b0f3ed04746ae267519eef2a83941e8085068b"
+checksum = "7d902e3d592a523def97af8f317b08ce16b7ab854c1985a0c671e6f15cebc236"
 
 [[package]]
 name = "assert-json-diff"
@@ -335,7 +335,7 @@ version = "2.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "47e4f2b81832e72834d7518d8487a0396a28cc408186a2e8854c0f98011faf12"
 dependencies = [
- "serde 1.0.219",
+ "serde",
  "serde_json",
 ]
 
@@ -388,6 +388,12 @@ dependencies = [
  "windows-targets 0.52.6",
 ]
 
+[[package]]
+name = "base64"
+version = "0.21.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9d297deb1925b89f2ccc13d7635fa0714f12c87adce1c75356b39ca9b7178567"
+
 [[package]]
 name = "base64"
 version = "0.22.1"
@@ -428,6 +434,9 @@ name = "bitflags"
 version = "2.9.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "34efbcccd345379ca2868b2b2c9d3782e9cc58ba87bc7d79d5b53d9c9ae6f25d"
+dependencies = [
+ "serde",
+]
 
 [[package]]
 name = "block-buffer"
@@ -521,7 +530,7 @@ version = "0.6.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6fac387a98bb7c37292057cffc56d62ecb629900026402633ae9160df93a8766"
 dependencies = [
- "nom 7.1.3",
+ "nom",
 ]
 
 [[package]]
@@ -545,7 +554,7 @@ dependencies = [
  "android-tzdata",
  "iana-time-zone",
  "js-sys",
- "num-traits 0.2.19",
+ "num-traits",
  "wasm-bindgen",
  "windows-link",
 ]
@@ -602,18 +611,51 @@ dependencies = [
 
 [[package]]
 name = "config"
-version = "0.11.0"
+version = "0.15.15"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1b1b9d958c2b1368a663f05538fc1b5975adce1e19f435acceae987aceeeb369"
+checksum = "0faa974509d38b33ff89282db9c3295707ccf031727c0de9772038ec526852ba"
 dependencies = [
- "lazy_static",
- "nom 5.1.3",
+ "async-trait",
+ "convert_case",
+ "json5",
+ "pathdiff",
+ "ron",
  "rust-ini",
- "serde 1.0.219",
- "serde-hjson",
+ "serde",
+ "serde-untagged",
  "serde_json",
- "toml 0.5.11",
- "yaml-rust",
+ "toml",
+ "winnow",
+ "yaml-rust2",
+]
+
+[[package]]
+name = "const-random"
+version = "0.1.18"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "87e00182fe74b066627d63b85fd550ac2998d4b0bd86bfed477a0ae4c7c71359"
+dependencies = [
+ "const-random-macro",
+]
+
+[[package]]
+name = "const-random-macro"
+version = "0.1.16"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f9d839f2a20b0aee515dc581a6172f2321f96cab76c1a38a4c584a194955390e"
+dependencies = [
+ "getrandom 0.2.16",
+ "once_cell",
+ "tiny-keccak",
+]
+
+[[package]]
+name = "convert_case"
+version = "0.6.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ec182b0ca2f35d8fc196cf3404988fd8b8c739a4d270ff118a398feb0cbec1ca"
+dependencies = [
+ "unicode-segmentation",
 ]
 
 [[package]]
@@ -655,6 +697,12 @@ version = "0.8.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d0a5c400df2834b80a4c3327b3aad3a4c4cd4de0629063962b03235697506a28"
 
+[[package]]
+name = "crunchy"
+version = "0.2.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "460fbee9c2c2f33933d720630a6a0bac33ba7053db5344fac858d4b8952d77d5"
+
 [[package]]
 name = "crypto-common"
 version = "0.1.6"
@@ -756,7 +804,7 @@ version = "0.8.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "bef552e6f588e446098f6ba40d89ac146c8c7b64aade83c051ee00bb5d2bc18d"
 dependencies = [
- "serde 1.0.219",
+ "serde",
  "uuid",
 ]
 
@@ -870,6 +918,15 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "dlv-list"
+version = "0.5.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "442039f5147480ba31067cb00ada1adae6892028e40e45fc5de7b7df6dcc1b5f"
+dependencies = [
+ "const-random",
+]
+
 [[package]]
 name = "docopt"
 version = "1.1.1"
@@ -878,7 +935,7 @@ checksum = "7f3f119846c823f9eafcf953a8f6ffb6ed69bf6240883261a7f13b634579a51f"
 dependencies = [
  "lazy_static",
  "regex",
- "serde 1.0.219",
+ "serde",
  "strsim 0.10.0",
 ]
 
@@ -965,7 +1022,17 @@ version = "0.3.31"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6c138974f9d5e7fe373eb04df7cae98833802ae4b11c24ac7039a21d5af4b26c"
 dependencies = [
- "serde 1.0.219",
+ "serde",
+]
+
+[[package]]
+name = "erased-serde"
+version = "0.4.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e004d887f51fcb9fef17317a2f3525c887d8aa3f4f50fed920816a688284a5b7"
+dependencies = [
+ "serde",
+ "typeid",
 ]
 
 [[package]]
@@ -1165,7 +1232,7 @@ name = "glean"
 version = "0.20.1"
 dependencies = [
  "chrono",
- "serde 1.0.219",
+ "serde",
  "serde_json",
  "uuid",
 ]
@@ -1256,11 +1323,29 @@ dependencies = [
  "tracing",
 ]
 
+[[package]]
+name = "hashbrown"
+version = "0.14.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e5274423e17b7c9fc20b6e7e208532f9b19825d82dfd615708b70edd83df41f1"
+
 [[package]]
 name = "hashbrown"
 version = "0.15.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9229cfe53dfd69f0609a49f65461bd93001ea1ef889cd5529dd176593f5338a1"
+dependencies = [
+ "foldhash",
+]
+
+[[package]]
+name = "hashlink"
+version = "0.10.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7382cf6263419f2d8df38c55d7da83da5c18aef87fc7a7fc1fb1e344edfe14c1"
+dependencies = [
+ "hashbrown 0.15.5",
+]
 
 [[package]]
 name = "hawk"
@@ -1269,7 +1354,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ab302457b3e28e621daab18932d67a67328f29240bfaa5f604b7627ece1eacda"
 dependencies = [
  "anyhow",
- "base64",
+ "base64 0.22.1",
  "log",
  "once_cell",
  "ring",
@@ -1451,7 +1536,7 @@ version = "0.1.16"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8d9b05277c7e8da2c93a568989bb6207bef0112e8d17df7a6eda4a3cf143bc5e"
 dependencies = [
- "base64",
+ "base64 0.22.1",
  "bytes",
  "futures-channel",
  "futures-core",
@@ -1619,7 +1704,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f2481980430f9f78649238835720ddccc57e52df14ffce1c6f37391d61b563e9"
 dependencies = [
  "equivalent",
- "hashbrown",
+ "hashbrown 0.15.5",
 ]
 
 [[package]]
@@ -1652,7 +1737,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "dbc5ebe9c3a1a7a5127f920a418f7585e9e758e911d0466ed004f393b0e380b2"
 dependencies = [
  "memchr",
- "serde 1.0.219",
+ "serde",
 ]
 
 [[package]]
@@ -1688,7 +1773,7 @@ dependencies = [
  "log",
  "portable-atomic",
  "portable-atomic-util",
- "serde 1.0.219",
+ "serde",
 ]
 
 [[package]]
@@ -1722,16 +1807,27 @@ dependencies = [
  "wasm-bindgen",
 ]
 
+[[package]]
+name = "json5"
+version = "0.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "96b0db21af676c1ce64250b5f40f3ce2cf27e4e47cb91ed91eb6fe9350b430c1"
+dependencies = [
+ "pest",
+ "pest_derive",
+ "serde",
+]
+
 [[package]]
 name = "jsonwebtoken"
 version = "9.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5a87cc7a48537badeae96744432de36f4be2b4a34a05a5ef32e9dd8a1c169dde"
 dependencies = [
- "base64",
+ "base64 0.22.1",
  "js-sys",
  "ring",
- "serde 1.0.219",
+ "serde",
  "serde_json",
 ]
 
@@ -1753,19 +1849,6 @@ version = "1.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "830d08ce1d1d941e6b30645f1a0eb5643013d835ce3779a5fc208261dbe10f55"
 
-[[package]]
-name = "lexical-core"
-version = "0.7.6"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6607c62aa161d23d17a9072cc5da0be67cdfc89d3afb1e8d9c842bebc2525ffe"
-dependencies = [
- "arrayvec",
- "bitflags 1.3.2",
- "cfg-if",
- "ryu",
- "static_assertions",
-]
-
 [[package]]
 name = "libc"
 version = "0.2.175"
@@ -1794,12 +1877,6 @@ dependencies = [
  "vcpkg",
 ]
 
-[[package]]
-name = "linked-hash-map"
-version = "0.5.6"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0717cef1bc8b636c6e1c1bbdefc09e6322da8a9321966e8928ef80d20f7f770f"
-
 [[package]]
 name = "linux-raw-sys"
 version = "0.4.15"
@@ -1872,8 +1949,8 @@ version = "2.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3bda1634d70d5bd53553cf15dca9842a396e8c799982a3ad22998dc44d961f24"
 dependencies = [
- "serde 1.0.219",
- "toml 0.9.5",
+ "serde",
+ "toml",
 ]
 
 [[package]]
@@ -1955,17 +2032,6 @@ dependencies = [
  "vcpkg",
 ]
 
-[[package]]
-name = "nom"
-version = "5.1.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "08959a387a676302eebf4ddbcbc611da04285579f76f88ee0506c63b1a61dd4b"
-dependencies = [
- "lexical-core",
- "memchr",
- "version_check",
-]
-
 [[package]]
 name = "nom"
 version = "7.1.3"
@@ -1982,15 +2048,6 @@ version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "51d515d32fb182ee37cda2ccdcb92950d6a3c2893aa280e540671c2cd0f3b1d9"
 
-[[package]]
-name = "num-traits"
-version = "0.1.43"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "92e5113e9fd4cc14ded8e499429f396a20f98c772a47cc8622a736e1ec843c31"
-dependencies = [
- "num-traits 0.2.19",
-]
-
 [[package]]
 name = "num-traits"
 version = "0.2.19"
@@ -2049,6 +2106,16 @@ dependencies = [
  "vcpkg",
 ]
 
+[[package]]
+name = "ordered-multimap"
+version = "0.7.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "49203cdcae0030493bad186b28da2fa25645fa276a51b6fec8010d281e02ef79"
+dependencies = [
+ "dlv-list",
+ "hashbrown 0.14.5",
+]
+
 [[package]]
 name = "os_info"
 version = "3.12.0"
@@ -2057,7 +2124,7 @@ checksum = "d0e1ac5fde8d43c34139135df8ea9ee9465394b2d8d20f032d38998f64afffc3"
 dependencies = [
  "log",
  "plist",
- "serde 1.0.219",
+ "serde",
  "windows-sys 0.52.0",
 ]
 
@@ -2084,6 +2151,12 @@ dependencies = [
  "windows-targets 0.52.6",
 ]
 
+[[package]]
+name = "pathdiff"
+version = "0.2.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "df94ce210e5bc13cb6651479fa48d14f601d9858cfe0467f43ae157023b938d3"
+
 [[package]]
 name = "peeking_take_while"
 version = "0.1.2"
@@ -2096,6 +2169,50 @@ version = "2.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9b4f627cb1b25917193a259e49bdad08f671f8d9708acfd5fe0a8c1455d87220"
 
+[[package]]
+name = "pest"
+version = "2.8.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1db05f56d34358a8b1066f67cbb203ee3e7ed2ba674a6263a1d5ec6db2204323"
+dependencies = [
+ "memchr",
+ "thiserror 2.0.16",
+ "ucd-trie",
+]
+
+[[package]]
+name = "pest_derive"
+version = "2.8.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bb056d9e8ea77922845ec74a1c4e8fb17e7c218cc4fc11a15c5d25e189aa40bc"
+dependencies = [
+ "pest",
+ "pest_generator",
+]
+
+[[package]]
+name = "pest_generator"
+version = "2.8.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "87e404e638f781eb3202dc82db6760c8ae8a1eeef7fb3fa8264b2ef280504966"
+dependencies = [
+ "pest",
+ "pest_meta",
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "pest_meta"
+version = "2.8.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "edd1101f170f5903fde0914f899bb503d9ff5271d7ba76bbb70bea63690cc0d5"
+dependencies = [
+ "pest",
+ "sha2",
+]
+
 [[package]]
 name = "pin-project-lite"
 version = "0.2.16"
@@ -2120,10 +2237,10 @@ version = "1.7.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3af6b589e163c5a788fab00ce0c0366f6efbb9959c2f9874b224936af7fce7e1"
 dependencies = [
- "base64",
+ "base64 0.22.1",
  "indexmap",
  "quick-xml",
- "serde 1.0.219",
+ "serde",
  "time",
 ]
 
@@ -2465,7 +2582,7 @@ version = "0.12.23"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d429f34c8092b2d42c7c93cec323bb4adeb7c67698f70839adec842ec10c7ceb"
 dependencies = [
- "base64",
+ "base64 0.22.1",
  "bytes",
  "futures-core",
  "http 1.3.1",
@@ -2481,7 +2598,7 @@ dependencies = [
  "quinn",
  "rustls",
  "rustls-pki-types",
- "serde 1.0.219",
+ "serde",
  "serde_json",
  "serde_urlencoded",
  "sync_wrapper",
@@ -2511,11 +2628,27 @@ dependencies = [
  "windows-sys 0.52.0",
 ]
 
+[[package]]
+name = "ron"
+version = "0.8.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b91f7eff05f748767f183df4320a63d6936e9c6107d97c9e6bdd9784f4289c94"
+dependencies = [
+ "base64 0.21.7",
+ "bitflags 2.9.3",
+ "serde",
+ "serde_derive",
+]
+
 [[package]]
 name = "rust-ini"
-version = "0.13.0"
+version = "0.21.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3e52c148ef37f8c375d49d5a73aa70713125b7f19095948a923f80afdeb22ec2"
+checksum = "796e8d2b6696392a43bea58116b667fb4c29727dc5abd27d6acf338bb4f688c7"
+dependencies = [
+ "cfg-if",
+ "ordered-multimap",
+]
 
 [[package]]
 name = "rustc-demangle"
@@ -2691,7 +2824,7 @@ checksum = "deaa38b94e70820ff3f1f9db3c8b0aef053b667be130f618e615e0ff2492cbcc"
 dependencies = [
  "rand 0.9.2",
  "sentry-types",
- "serde 1.0.219",
+ "serde",
  "serde_json",
  "url",
 ]
@@ -2728,7 +2861,7 @@ dependencies = [
  "debugid",
  "hex",
  "rand 0.9.2",
- "serde 1.0.219",
+ "serde",
  "serde_json",
  "thiserror 2.0.16",
  "time",
@@ -2736,12 +2869,6 @@ dependencies = [
  "uuid",
 ]
 
-[[package]]
-name = "serde"
-version = "0.8.23"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9dad3f759919b92c3068c696c15c3d17238234498bbdcc80f2c469606f948ac8"
-
 [[package]]
 name = "serde"
 version = "1.0.219"
@@ -2752,15 +2879,14 @@ dependencies = [
 ]
 
 [[package]]
-name = "serde-hjson"
-version = "0.9.1"
+name = "serde-untagged"
+version = "0.1.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6a3a4e0ea8a88553209f6cc6cfe8724ecad22e1acf372793c27d995290fe74f8"
+checksum = "34836a629bcbc6f1afdf0907a744870039b1e14c0561cb26094fa683b158eff3"
 dependencies = [
- "lazy_static",
- "num-traits 0.1.43",
- "regex",
- "serde 0.8.23",
+ "erased-serde 0.4.6",
+ "serde",
+ "typeid",
 ]
 
 [[package]]
@@ -2783,7 +2909,7 @@ dependencies = [
  "itoa",
  "memchr",
  "ryu",
- "serde 1.0.219",
+ "serde",
 ]
 
 [[package]]
@@ -2792,7 +2918,7 @@ version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "40734c41988f7306bb04f0ecf60ec0f3f1caa34290e4e8ea471dcd3346483b83"
 dependencies = [
- "serde 1.0.219",
+ "serde",
 ]
 
 [[package]]
@@ -2804,7 +2930,7 @@ dependencies = [
  "form_urlencoded",
  "itoa",
  "ryu",
- "serde 1.0.219",
+ "serde",
 ]
 
 [[package]]
@@ -2862,7 +2988,7 @@ version = "2.7.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8347046d4ebd943127157b94d63abb990fcf729dc4e9978927fdf4ac3c998d06"
 dependencies = [
- "erased-serde",
+ "erased-serde 0.3.31",
 ]
 
 [[package]]
@@ -2899,7 +3025,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f400f1c5db96f1f52065e8931ca0c524cceb029f7537c9e6d5424488ca137ca0"
 dependencies = [
  "chrono",
- "serde 1.0.219",
+ "serde",
  "serde_json",
  "slog",
 ]
@@ -2972,12 +3098,6 @@ version = "1.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a8f112729512f8e442d81f95a8a7ddf2b7c6b8a1a6f509a95864142b30cab2d3"
 
-[[package]]
-name = "static_assertions"
-version = "1.1.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a2eb9349b6444b326872e140eb1cf5e7c522154d69e7a0ffb0fb81c06b37543f"
-
 [[package]]
 name = "strsim"
 version = "0.8.0"
@@ -3031,7 +3151,7 @@ dependencies = [
  "actix-rt",
  "actix-web",
  "backtrace",
- "base64",
+ "base64 0.22.1",
  "cadence",
  "chrono",
  "docopt",
@@ -3047,7 +3167,7 @@ dependencies = [
  "rand 0.8.5",
  "regex",
  "sentry",
- "serde 1.0.219",
+ "serde",
  "serde_json",
  "sha2",
  "slog",
@@ -3114,7 +3234,7 @@ version = "0.20.1"
 dependencies = [
  "config",
  "num_cpus",
- "serde 1.0.219",
+ "serde",
  "slog-scope",
  "syncserver-common",
  "syncstorage-settings",
@@ -3154,7 +3274,7 @@ dependencies = [
  "futures 0.3.31",
  "http 1.3.1",
  "lazy_static",
- "serde 1.0.219",
+ "serde",
  "serde_json",
  "syncserver-common",
  "syncserver-db-common",
@@ -3167,7 +3287,7 @@ version = "0.20.1"
 dependencies = [
  "async-trait",
  "backtrace",
- "base64",
+ "base64 0.22.1",
  "diesel",
  "diesel_logger",
  "diesel_migrations",
@@ -3189,7 +3309,7 @@ name = "syncstorage-settings"
 version = "0.20.1"
 dependencies = [
  "rand 0.8.5",
- "serde 1.0.219",
+ "serde",
  "syncserver-common",
  "time",
 ]
@@ -3327,7 +3447,7 @@ dependencies = [
  "itoa",
  "num-conv",
  "powerfmt",
- "serde 1.0.219",
+ "serde",
  "time-core",
  "time-macros",
 ]
@@ -3348,6 +3468,15 @@ dependencies = [
  "time-core",
 ]
 
+[[package]]
+name = "tiny-keccak"
+version = "2.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2c9d3793400a45f954c52e73d068316d76b6f4e36977e3fcebb13a2721e80237"
+dependencies = [
+ "crunchy",
+]
+
 [[package]]
 name = "tinystr"
 version = "0.8.1"
@@ -3378,7 +3507,7 @@ name = "tokenserver-auth"
 version = "0.20.1"
 dependencies = [
  "async-trait",
- "base64",
+ "base64 0.22.1",
  "dyn-clone",
  "hex",
  "hkdf",
@@ -3388,7 +3517,7 @@ dependencies = [
  "pyo3",
  "reqwest",
  "ring",
- "serde 1.0.219",
+ "serde",
  "serde_json",
  "sha2",
  "slog-scope",
@@ -3407,7 +3536,7 @@ dependencies = [
  "backtrace",
  "http 1.3.1",
  "pyo3",
- "serde 1.0.219",
+ "serde",
  "syncserver-common",
 ]
 
@@ -3423,7 +3552,7 @@ dependencies = [
  "env_logger 0.11.8",
  "futures 0.3.31",
  "http 1.3.1",
- "serde 1.0.219",
+ "serde",
  "slog-scope",
  "syncserver-common",
  "syncserver-db-common",
@@ -3439,7 +3568,7 @@ name = "tokenserver-settings"
 version = "0.20.1"
 dependencies = [
  "jsonwebtoken",
- "serde 1.0.219",
+ "serde",
  "tokenserver-common",
 ]
 
@@ -3497,15 +3626,6 @@ dependencies = [
  "tokio",
 ]
 
-[[package]]
-name = "toml"
-version = "0.5.11"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f4f7f0dd8d50a853a531c426359045b1998f04219d88799810762cd4ad314234"
-dependencies = [
- "serde 1.0.219",
-]
-
 [[package]]
 name = "toml"
 version = "0.9.5"
@@ -3513,7 +3633,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "75129e1dc5000bfbaa9fee9d1b21f974f9fbad9daec557a521ee6e080825f6e8"
 dependencies = [
  "indexmap",
- "serde 1.0.219",
+ "serde",
  "serde_spanned",
  "toml_datetime",
  "toml_parser",
@@ -3527,7 +3647,7 @@ version = "0.7.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "bade1c3e902f58d73d3f294cd7f20391c1cb2fbcb643b73566bc773971df91e3"
 dependencies = [
- "serde 1.0.219",
+ "serde",
 ]
 
 [[package]]
@@ -3638,12 +3758,24 @@ version = "0.2.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e421abadd41a4225275504ea4d6566923418b7f05506fbc9c0fe86ba7396114b"
 
+[[package]]
+name = "typeid"
+version = "1.0.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bc7d623258602320d5c55d1bc22793b57daff0ec7efc270ea7d55ce1d5f5471c"
+
 [[package]]
 name = "typenum"
 version = "1.18.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1dccffe3ce07af9386bfd29e80c0ab1a8205a2fc34e4bcd40364df902cfa8f3f"
 
+[[package]]
+name = "ucd-trie"
+version = "0.1.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2896d95c02a80c6d6a5d6e953d479f5ddf2dfdb6a244441010e373ac0fb88971"
+
 [[package]]
 name = "uname"
 version = "0.1.1"
@@ -3659,6 +3791,12 @@ version = "1.0.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5a5f39404a5da50712a4c1eecf25e90dd62b613502b7e925fd4e4d19b5c96512"
 
+[[package]]
+name = "unicode-segmentation"
+version = "1.12.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f6ccf251212114b54433ec949fd6a7841275f9ada20dddd2f29e9ceea4501493"
+
 [[package]]
 name = "unicode-width"
 version = "0.1.14"
@@ -3692,7 +3830,7 @@ dependencies = [
  "form_urlencoded",
  "idna",
  "percent-encoding",
- "serde 1.0.219",
+ "serde",
 ]
 
 [[package]]
@@ -3721,7 +3859,7 @@ checksum = "f33196643e165781c20a5ead5582283a7dacbb87855d867fbc2df3f81eddc1be"
 dependencies = [
  "getrandom 0.3.3",
  "js-sys",
- "serde 1.0.219",
+ "serde",
  "wasm-bindgen",
 ]
 
@@ -3734,7 +3872,7 @@ dependencies = [
  "idna",
  "once_cell",
  "regex",
- "serde 1.0.219",
+ "serde",
  "serde_derive",
  "serde_json",
  "url",
@@ -4175,6 +4313,9 @@ name = "winnow"
 version = "0.7.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "21a0236b59786fed61e2a80582dd500fe61f18b5dca67a4a067d0bc9039339cf"
+dependencies = [
+ "memchr",
+]
 
 [[package]]
 name = "wit-bindgen"
@@ -4199,12 +4340,14 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ea2f10b9bb0928dfb1b42b65e1f9e36f7f54dbdf08457afefb38afcdec4fa2bb"
 
 [[package]]
-name = "yaml-rust"
-version = "0.4.5"
+name = "yaml-rust2"
+version = "0.10.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "56c1936c4cc7a1c9ab21a1ebb602eb942ba868cbd44a99cb7cdc5892335e1c85"
+checksum = "4ce2a4ff45552406d02501cea6c18d8a7e50228e7736a872951fe2fe75c91be7"
 dependencies = [
- "linked-hash-map",
+ "arraydeque",
+ "encoding_rs",
+ "hashlink",
 ]
 
 [[package]]
@@ -4213,7 +4356,7 @@ version = "0.8.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5f41bb01b8226ef4bfd589436a297c53d118f65921786300e427be8d487695cc"
 dependencies = [
- "serde 1.0.219",
+ "serde",
  "stable_deref_trait",
  "yoke-derive",
  "zerofrom",
diff --git a/syncserver-settings/Cargo.toml b/syncserver-settings/Cargo.toml
index b64309cfa9..998a4529cd 100644
--- a/syncserver-settings/Cargo.toml
+++ b/syncserver-settings/Cargo.toml
@@ -9,7 +9,7 @@ edition.workspace = true
 serde.workspace = true
 slog-scope.workspace = true
 
-config = "0.11"                                             # pin to 11, 12+ introduces a breaking change for env vars.
+config = "0.15"                                             # pin to 11, 12+ introduces a breaking change for env vars.
 num_cpus = "1"
 syncserver-common = { path = "../syncserver-common" }
 syncstorage-settings = { path = "../syncstorage-settings" }
diff --git a/syncserver-settings/src/lib.rs b/syncserver-settings/src/lib.rs
index 6732ffcc0c..a5e0367d88 100644
--- a/syncserver-settings/src/lib.rs
+++ b/syncserver-settings/src/lib.rs
@@ -52,11 +52,11 @@ pub struct Settings {
 impl Settings {
     /// Load the settings from the config file if supplied, then the environment.
     pub fn with_env_and_config_file(filename: Option<&str>) -> Result<Self, ConfigError> {
-        let mut s = Config::default();
+        let mut builder = Config::builder();
 
         // Merge the config file if supplied
         if let Some(config_filename) = filename {
-            s.merge(File::with_name(config_filename))?;
+            builder = builder.add_source(File::with_name(config_filename));
         }
 
         // Merge the environment overrides
@@ -65,25 +65,28 @@ impl Settings {
         // Environment ever change their policy about case insensitivity.
         // This will accept environment variables specified as
         // `SYNC_FOO__BAR_VALUE="gorp"` as `foo.bar_value = "gorp"`
-        s.merge(Environment::with_prefix(&PREFIX.to_uppercase()).separator("__"))?;
+        builder =
+            builder.add_source(Environment::with_prefix(&PREFIX.to_uppercase()).separator("__"));
+        let settings: Config = builder.build()?;
 
-        match s.try_into::<Self>() {
-            Ok(mut s) => {
-                s.syncstorage.normalize();
-                if s.worker_max_blocking_threads == 0 {
+        match settings.try_deserialize::<Self>() {
+            Ok(mut settings) => {
+                settings.syncstorage.normalize();
+                if settings.worker_max_blocking_threads == 0 {
                     // Db backends w/ blocking calls block via
                     // actix-threadpool: grow its size to accommodate the
                     // full number of connections
                     let total_db_pool_size = {
-                        let syncstorage_pool_max_size =
-                            if s.syncstorage.uses_spanner() || !s.syncstorage.enabled {
-                                0
-                            } else {
-                                s.syncstorage.database_pool_max_size
-                            };
+                        let syncstorage_pool_max_size = if settings.syncstorage.uses_spanner()
+                            || !settings.syncstorage.enabled
+                        {
+                            0
+                        } else {
+                            settings.syncstorage.database_pool_max_size
+                        };
 
-                        let tokenserver_pool_max_size = if s.tokenserver.enabled {
-                            s.tokenserver.database_pool_max_size
+                        let tokenserver_pool_max_size = if settings.tokenserver.enabled {
+                            settings.tokenserver.database_pool_max_size
                         } else {
                             0
                         };
@@ -91,11 +94,11 @@ impl Settings {
                         syncstorage_pool_max_size + tokenserver_pool_max_size
                     };
 
-                    let fxa_threads = if s.tokenserver.enabled
-                        && s.tokenserver.fxa_oauth_primary_jwk.is_none()
-                        && s.tokenserver.fxa_oauth_secondary_jwk.is_none()
+                    let fxa_threads = if settings.tokenserver.enabled
+                        && settings.tokenserver.fxa_oauth_primary_jwk.is_none()
+                        && settings.tokenserver.fxa_oauth_secondary_jwk.is_none()
                     {
-                        s.tokenserver
+                        settings.tokenserver
                             .additional_blocking_threads_for_fxa_requests
                             .ok_or_else(|| {
                                 println!(
@@ -110,10 +113,10 @@ impl Settings {
                     } else {
                         0
                     };
-                    s.worker_max_blocking_threads =
+                    settings.worker_max_blocking_threads =
                         (total_db_pool_size + fxa_threads).max(num_cpus::get() as u32 * 5) as usize;
                 }
-                Ok(s)
+                Ok(settings)
             }
             // Configuration errors are not very sysop friendly, Try to make them
             // a bit more 3AM useful.