diff --git a/Cargo.lock b/Cargo.lock
index dec3d9a9..a338db5f 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -4,18 +4,18 @@ version = 4
 
 [[package]]
 name = "adblock"
-version = "0.9.6"
+version = "0.9.5"
 dependencies = [
  "addr",
- "base64 0.22.1",
- "bitflags 2.9.0",
+ "base64 0.13.0",
+ "bitflags",
  "criterion",
  "cssparser",
  "csv",
- "flatbuffers",
  "futures",
  "idna",
  "itertools 0.13.0",
+ "lifeguard",
  "memchr",
  "mock_instant",
  "once_cell",
@@ -82,27 +82,12 @@ version = "0.21.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9d297deb1925b89f2ccc13d7635fa0714f12c87adce1c75356b39ca9b7178567"
 
-[[package]]
-name = "base64"
-version = "0.22.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "72b3254f16251a8381aa12e40e3c4d2f0199f8c6508fbecb9d91f575e0fbb8c6"
-
 [[package]]
 name = "bitflags"
 version = "1.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "bef38d45163c2f1dde094a7dfd33ccf595c92905c8f8f4fdc18d06fb1037718a"
 
-[[package]]
-name = "bitflags"
-version = "2.9.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5c8214115b7bf84099f1309324e63141d4c5d7cc26862f97a0a857dbefe165bd"
-dependencies = [
- "serde",
-]
-
 [[package]]
 name = "block-buffer"
 version = "0.9.0"
@@ -393,7 +378,7 @@ checksum = "97369cbbc041bc366949bc74d34658d6cda5621039731c6310521892a3a20ae0"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.61",
+ "syn 2.0.100",
 ]
 
 [[package]]
@@ -432,16 +417,6 @@ version = "1.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5443807d6dff69373d433ab9ef5378ad8df50ca6298caf15de6e52e24aaf54d5"
 
-[[package]]
-name = "flatbuffers"
-version = "25.2.10"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1045398c1bfd89168b5fd3f1fc11f6e70b34f6f66300c87d44d3de849463abf1"
-dependencies = [
- "bitflags 2.9.0",
- "rustc_version",
-]
-
 [[package]]
 name = "fnv"
 version = "1.0.7"
@@ -513,7 +488,7 @@ checksum = "162ee34ebcb7c64a8abebc059ce0fee27c2262618d7b60ed8faf72fef13c3650"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.61",
+ "syn 2.0.100",
 ]
 
 [[package]]
@@ -820,7 +795,7 @@ checksum = "1ec89e9337638ecdc08744df490b221a7399bf8d164eb52a665454e60e075ad6"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.61",
+ "syn 2.0.100",
 ]
 
 [[package]]
@@ -910,6 +885,12 @@ version = "0.2.150"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "89d92a4743f9a61002fae18374ed11e7973f530cb3a3255fb354818118b2203c"
 
+[[package]]
+name = "lifeguard"
+version = "0.6.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "89be94dbd775db37b46ca4f4bf5cf89adfb13ba197bfbcb69b2122848ee73c26"
+
 [[package]]
 name = "litemap"
 version = "0.7.4"
@@ -1139,9 +1120,9 @@ checksum = "dbf0c48bc1d91375ae5c3cd81e3722dff1abcf81a30960240640d223f59fe0e5"
 
 [[package]]
 name = "proc-macro2"
-version = "1.0.82"
+version = "1.0.94"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8ad3d49ab951a01fbaafe34f2ec74122942fe18a3f9814c3268f1bb72042131b"
+checksum = "a31971752e70b8b2686d7e46ec17fb38dad4051d94024c88df49b667caea9c84"
 dependencies = [
  "unicode-ident",
 ]
@@ -1438,9 +1419,9 @@ dependencies = [
 
 [[package]]
 name = "seahash"
-version = "4.1.0"
+version = "3.0.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1c107b6f4780854c8b126e228ea8869f4d7b71260f962fefb57b996b8959ba6b"
+checksum = "58f57ca1d128a43733fd71d583e837b1f22239a37ebea09cde11d8d9a9080f47"
 
 [[package]]
 name = "selectors"
@@ -1448,7 +1429,7 @@ version = "0.24.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0c37578180969d00692904465fb7f6b3d50b9a2b952b87c23d0e2e5cb5013416"
 dependencies = [
- "bitflags 1.3.2",
+ "bitflags",
  "cssparser",
  "derive_more",
  "fxhash",
@@ -1468,22 +1449,22 @@ checksum = "e25dfac463d778e353db5be2449d1cce89bd6fd23c9f1ea21310ce6e5a1b29c4"
 
 [[package]]
 name = "serde"
-version = "1.0.210"
+version = "1.0.219"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c8e3592472072e6e22e0a54d5904d9febf8508f65fb8552499a1abc7d1078c3a"
+checksum = "5f0e2c6ed6606019b4e29e69dbaba95b11854410e5347d525002456dbbb786b6"
 dependencies = [
  "serde_derive",
 ]
 
 [[package]]
 name = "serde_derive"
-version = "1.0.210"
+version = "1.0.219"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "243902eda00fad750862fc144cea25caca5e20d615af0a81bee94ca738f1df1f"
+checksum = "5b0276cf7f2c73365f7157c8123c21cd9a50fbbd844757af28ca1f5925fc2a00"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.61",
+ "syn 2.0.100",
 ]
 
 [[package]]
@@ -1595,9 +1576,9 @@ dependencies = [
 
 [[package]]
 name = "syn"
-version = "2.0.61"
+version = "2.0.100"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c993ed8ccba56ae856363b1845da7266a7cb78e1d146c8a32d54b45a8b831fc9"
+checksum = "b09a44accad81e1ba1cd74a32461ba89dee89095ba17b32f5d03683b1b1fc2a0"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -1612,7 +1593,7 @@ checksum = "c8af7666ab7b6390ab78131fb5b0fce11d6b7a6951602017c35fa82800708971"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.61",
+ "syn 2.0.100",
 ]
 
 [[package]]
@@ -1621,7 +1602,7 @@ version = "0.5.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ba3a3adc5c275d719af8cb4272ea1c4a6d668a777f37e115f6d11ddbc1c8e0e7"
 dependencies = [
- "bitflags 1.3.2",
+ "bitflags",
  "core-foundation",
  "system-configuration-sys",
 ]
@@ -1653,7 +1634,7 @@ checksum = "ae71770322cbd277e69d762a16c444af02aa0575ac0d174f0b9562d3b37f8602"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.61",
+ "syn 2.0.100",
 ]
 
 [[package]]
@@ -2186,7 +2167,7 @@ checksum = "2380878cad4ac9aac1e2435f3eb4020e8374b5f13c296cb75b4620ff8e229154"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.61",
+ "syn 2.0.100",
  "synstructure",
 ]
 
@@ -2207,7 +2188,7 @@ checksum = "595eed982f7d355beb85837f651fa22e90b3c044842dc7f2c2842c086f295808"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.61",
+ "syn 2.0.100",
  "synstructure",
 ]
 
@@ -2230,5 +2211,5 @@ checksum = "6eafa6dfb17584ea3e2bd6e76e0cc15ad7af12b09abdd1ca55961bed9b1063c6"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.61",
+ "syn 2.0.100",
 ]
diff --git a/Cargo.toml b/Cargo.toml
index b857bba2..27697390 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "adblock"
-version = "0.9.6"
+version = "0.9.5"
 authors = ["Anton Lazarev <alazarev@brave.com>", "Andrius Aucinas"]
 edition = "2021"
 
@@ -28,19 +28,19 @@ url = "2.5"
 percent-encoding = "2.1"
 once_cell = "1.8"
 regex = "1.5"
-bitflags = { version = "2.9.0", features = ["serde"] }
+bitflags = "1.3"
 itertools = "0.13"
 idna = "1.0.3"
 serde =  { version = "1.0", features = ["derive", "rc"] }
-seahash = "4.1.0"
+seahash = "3"   # seahash 4 introduces a breaking hash algorithm change
 memchr = "2.4"
-base64 = "0.22"
+base64 = "0.13"
 rmp-serde = "0.15"
+lifeguard = { version = "^ 0.6.1", optional = true }
 cssparser = { version = "0.29", optional = true }
 selectors = { version = "0.24", optional = true }
 serde_json = "1.0"
 thiserror = "1.0"
-flatbuffers = { version = "25.2.10", optional = true }
 
 [dev-dependencies]
 criterion = "0.5"
@@ -89,12 +89,12 @@ harness = false
 [features]
 # If disabling default features, consider explicitly re-enabling the
 # "embedded-domain-resolver" feature.
-default = ["embedded-domain-resolver", "full-regex-handling", "unsync-regex-caching"]
+default = ["embedded-domain-resolver", "full-regex-handling", "object-pooling", "unsync-regex-caching"]
 full-regex-handling = []
+object-pooling = ["lifeguard"] # disables `Send` and `Sync` on `Engine`.
 unsync-regex-caching = [] # disables `Send` and `Sync` on `Engine`.
 regex-debug-info = []
 css-validation = ["cssparser", "selectors"]
 content-blocking = []
 embedded-domain-resolver = ["addr"] # Requires setting an external domain resolver if disabled.
 resource-assembler = []
-flatbuffers-storage = [ "flatbuffers" ]
diff --git a/js/Cargo.lock b/js/Cargo.lock
index 72123f92..3c0d924c 100644
--- a/js/Cargo.lock
+++ b/js/Cargo.lock
@@ -719,18 +719,18 @@ checksum = "388a1df253eca08550bef6c72392cfe7c30914bf41df5269b68cbd6ff8f570a3"
 
 [[package]]
 name = "serde"
-version = "1.0.215"
+version = "1.0.219"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6513c1ad0b11a9376da888e3e0baa0077f1aed55c17f50e7b2397136129fb88f"
+checksum = "5f0e2c6ed6606019b4e29e69dbaba95b11854410e5347d525002456dbbb786b6"
 dependencies = [
  "serde_derive",
 ]
 
 [[package]]
 name = "serde_derive"
-version = "1.0.215"
+version = "1.0.219"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ad1e866f866923f252f05c889987993144fb74e722403468a4ebd70c3cd756c0"
+checksum = "5b0276cf7f2c73365f7157c8123c21cd9a50fbbd844757af28ca1f5925fc2a00"
 dependencies = [
  "proc-macro2",
  "quote",