diff --git a/backend/Cargo.lock b/backend/Cargo.lock
index 7733ead..db0e0ef 100644
--- a/backend/Cargo.lock
+++ b/backend/Cargo.lock
@@ -1003,6 +1003,16 @@ dependencies = [
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "proc-macro-error"
+version = "0.2.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "proc-macro2 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "proc-macro2"
 version = "0.4.30"
@@ -1400,22 +1410,23 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "structopt"
-version = "0.2.18"
+version = "0.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "clap 2.33.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "structopt-derive 0.2.18 (registry+https://github.com/rust-lang/crates.io-index)",
+ "structopt-derive 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "structopt-derive"
-version = "0.2.18"
+version = "0.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "heck 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "proc-macro2 0.4.30 (registry+https://github.com/rust-lang/crates.io-index)",
- "quote 0.6.13 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.15.41 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro-error 0.2.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -1896,7 +1907,7 @@ dependencies = [
  "serde 1.0.100 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_derive 1.0.100 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_json 1.0.40 (registry+https://github.com/rust-lang/crates.io-index)",
- "structopt 0.2.18 (registry+https://github.com/rust-lang/crates.io-index)",
+ "structopt 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "time-cache 0.1.0",
 ]
 
@@ -2004,6 +2015,7 @@ dependencies = [
 "checksum percent-encoding 2.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "d4fd5641d01c8f18a23da7b6fe29298ff4b55afcccdf78973b24cf3175fee32e"
 "checksum ppv-lite86 0.2.5 (registry+https://github.com/rust-lang/crates.io-index)" = "e3cbf9f658cdb5000fcf6f362b8ea2ba154b9f146a61c7a20d647034c6b6561b"
 "checksum pretty_env_logger 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)" = "717ee476b1690853d222af4634056d830b5197ffd747726a9a1eee6da9f49074"
+"checksum proc-macro-error 0.2.6 (registry+https://github.com/rust-lang/crates.io-index)" = "aeccfe4d5d8ea175d5f0e4a2ad0637e0f4121d63bd99d356fb1f39ab2e7c6097"
 "checksum proc-macro2 0.4.30 (registry+https://github.com/rust-lang/crates.io-index)" = "cf3d2011ab5c909338f7887f4fc896d35932e29146c12c8d01da6b22a80ba759"
 "checksum proc-macro2 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)" = "4c5c2380ae88876faae57698be9e9775e3544decad214599c3a6266cca6ac802"
 "checksum quick-error 1.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "9274b940887ce9addde99c4eee6b5c44cc494b182b97e73dc8ffdcb3397fd3f0"
@@ -2052,8 +2064,8 @@ dependencies = [
 "checksum stable_deref_trait 1.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "dba1a27d3efae4351c8051072d619e3ade2820635c3958d826bfea39d59b54c8"
 "checksum string 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "d24114bfcceb867ca7f71a0d3fe45d45619ec47a6fbfa98cb14e14250bfa5d6d"
 "checksum strsim 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)" = "8ea5119cdb4c55b55d432abb513a0429384878c15dde60cc77b1c99de1a95a6a"
-"checksum structopt 0.2.18 (registry+https://github.com/rust-lang/crates.io-index)" = "16c2cdbf9cc375f15d1b4141bc48aeef444806655cd0e904207edc8d68d86ed7"
-"checksum structopt-derive 0.2.18 (registry+https://github.com/rust-lang/crates.io-index)" = "53010261a84b37689f9ed7d395165029f9cc7abb9f56bbfe86bee2597ed25107"
+"checksum structopt 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)" = "2ac9d6e93dd792b217bf89cda5c14566e3043960c6f9da890c2ba5d09d07804c"
+"checksum structopt-derive 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)" = "2ae9e5165d463a0dea76967d021f8d0f9316057bf5163aa2a4843790e842ff37"
 "checksum syn 0.15.41 (registry+https://github.com/rust-lang/crates.io-index)" = "5f48d3b9d3d5ee64217007ead81e80d40674c80e930cf53ed089f0f809fae31e"
 "checksum syn 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)" = "158521e6f544e7e3dcfc370ac180794aa38cb34a1b1e07609376d4adcf429b93"
 "checksum synstructure 0.10.2 (registry+https://github.com/rust-lang/crates.io-index)" = "02353edf96d6e4dc81aea2d8490a7e9db177bf8acb0e951c24940bf866cb313f"
diff --git a/backend/Cargo.toml b/backend/Cargo.toml
index 80a2664..88dc470 100644
--- a/backend/Cargo.toml
+++ b/backend/Cargo.toml
@@ -19,5 +19,5 @@ pretty_env_logger = "0.3.1"
 serde = { version = "1.0.100", features = ["rc"] }
 serde_derive = "1.0.100"
 serde_json = "1.0.40"
-structopt = "0.2.18"
+structopt = "0.3.1"
 time-cache = { path = "../time-cache" }