diff --git a/Cargo.toml b/Cargo.toml
index 15fcdc747..dba8651a7 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -17,8 +17,7 @@ byteorder = "1.0"
 lazy_static = "1"
 regex = "1.0"
 tantivy-fst = "0.1"
-memmap = "0.7"
-fst-regex = { version="0.2" }
+memmap = {version = "0.7", optional=true}
 lz4 = {version="1.20", optional=true}
 snap = {version="0.2"}
 atomicwrites = {version="0.2.2", optional=true}
@@ -34,7 +33,7 @@ fs2={version="0.4", optional=true}
 itertools = "0.8"
 levenshtein_automata = {version="0.1", features=["fst_automaton"]}
 bit-set = "0.5"
-uuid = { version = "0.7", features = ["v4", "serde"] }
+uuid = { version = "0.7.2", features = ["v4", "serde"] }
 crossbeam = "0.5"
 futures = "0.1"
 futures-cpupool = "0.1"
@@ -72,12 +71,11 @@ overflow-checks = true
 [features]
 # by default no-fail is disabled. We manually enable it when running test.
 default = ["mmap", "no_fail"]
-mmap = ["atomicwrites", "fs2"]
+mmap = ["atomicwrites", "fs2",  "memmap"]
 lz4-compression = ["lz4"]
 no_fail = ["fail/no_fail"]
 unstable = [] # useful for benches.
+wasm-bindgen = ["uuid/wasm-bindgen"]
 
 [badges]
 travis-ci = { repository = "tantivy-search/tantivy" }
-
-