diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,7 +1,22 @@
+<!--
+SPDX-FileCopyrightText: 2019 Serokell <https://serokell.io>
+
+SPDX-License-Identifier: MPL-2.0
+-->
+
 Change log
 ==========
 o'clock uses [PVP Versioning][1].
 The change log is available [on GitHub][2].
+
+1.2.0
+=====
+
+* [#113](https://github.com/serokell/o-clock/pull/113):
+  + Increase some upper bounds.
+  + Drop support for GHC-8.4.
+  + Drop `deepseq`, `serialize` and `hashable` flags.
+  + Fix some warnings.
 
 1.1.0
 =====
diff --git a/LICENSE b/LICENSE
--- a/LICENSE
+++ b/LICENSE
@@ -1,21 +1,312 @@
-MIT License
+Mozilla Public License Version 2.0
 
-Copyright (c) 2018 Serokell
+   1. Definitions
 
-Permission is hereby granted, free of charge, to any person obtaining a copy
-of this software and associated documentation files (the "Software"), to deal
-in the Software without restriction, including without limitation the rights
-to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-copies of the Software, and to permit persons to whom the Software is
-furnished to do so, subject to the following conditions:
+1.1. "Contributor" means each individual or legal entity that creates, contributes
+to the creation of, or owns Covered Software.
 
-The above copyright notice and this permission notice shall be included in all
-copies or substantial portions of the Software.
+1.2. "Contributor Version" means the combination of the Contributions of others
+(if any) used by a Contributor and that particular Contributor's Contribution.
 
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-SOFTWARE.
+      1.3. "Contribution" means Covered Software of a particular Contributor.
+
+1.4. "Covered Software" means Source Code Form to which the initial Contributor
+has attached the notice in Exhibit A, the Executable Form of such Source Code
+Form, and Modifications of such Source Code Form, in each case including portions
+thereof.
+
+      1.5. "Incompatible With Secondary Licenses" means
+
+(a) that the initial Contributor has attached the notice described in Exhibit
+B to the Covered Software; or
+
+(b) that the Covered Software was made available under the terms of version
+1.1 or earlier of the License, but not also under the terms of a Secondary
+License.
+
+1.6. "Executable Form" means any form of the work other than Source Code Form.
+
+1.7. "Larger Work" means a work that combines Covered Software with other
+material, in a separate file or files, that is not Covered Software.
+
+      1.8. "License" means this document.
+
+1.9. "Licensable" means having the right to grant, to the maximum extent possible,
+whether at the time of the initial grant or subsequently, any and all of the
+rights conveyed by this License.
+
+      1.10. "Modifications" means any of the following:
+
+(a) any file in Source Code Form that results from an addition to, deletion
+from, or modification of the contents of Covered Software; or
+
+(b) any new file in Source Code Form that contains any Covered Software.
+
+1.11. "Patent Claims" of a Contributor means any patent claim(s), including
+without limitation, method, process, and apparatus claims, in any patent Licensable
+by such Contributor that would be infringed, but for the grant of the License,
+by the making, using, selling, offering for sale, having made, import, or
+transfer of either its Contributions or its Contributor Version.
+
+1.12. "Secondary License" means either the GNU General Public License, Version
+2.0, the GNU Lesser General Public License, Version 2.1, the GNU Affero General
+Public License, Version 3.0, or any later versions of those licenses.
+
+1.13. "Source Code Form" means the form of the work preferred for making modifications.
+
+1.14. "You" (or "Your") means an individual or a legal entity exercising rights
+under this License. For legal entities, "You" includes any entity that controls,
+is controlled by, or is under common control with You. For purposes of this
+definition, "control" means (a) the power, direct or indirect, to cause the
+direction or management of such entity, whether by contract or otherwise,
+or (b) ownership of more than fifty percent (50%) of the outstanding shares
+or beneficial ownership of such entity.
+
+   2. License Grants and Conditions
+
+      2.1. Grants
+
+Each Contributor hereby grants You a world-wide, royalty-free, non-exclusive
+license:
+
+(a) under intellectual property rights (other than patent or trademark) Licensable
+by such Contributor to use, reproduce, make available, modify, display, perform,
+distribute, and otherwise exploit its Contributions, either on an unmodified
+basis, with Modifications, or as part of a Larger Work; and
+
+(b) under Patent Claims of such Contributor to make, use, sell, offer for
+sale, have made, import, and otherwise transfer either its Contributions or
+its Contributor Version.
+
+      2.2. Effective Date
+
+The licenses granted in Section 2.1 with respect to any Contribution become
+effective for each Contribution on the date the Contributor first distributes
+such Contribution.
+
+      2.3. Limitations on Grant Scope
+
+The licenses granted in this Section 2 are the only rights granted under this
+License. No additional rights or licenses will be implied from the distribution
+or licensing of Covered Software under this License. Notwithstanding Section
+2.1(b) above, no patent license is granted by a Contributor:
+
+(a) for any code that a Contributor has removed from Covered Software; or
+
+(b) for infringements caused by: (i) Your and any other third party's modifications
+of Covered Software, or (ii) the combination of its Contributions with other
+software (except as part of its Contributor Version); or
+
+(c) under Patent Claims infringed by Covered Software in the absence of its
+Contributions.
+
+This License does not grant any rights in the trademarks, service marks, or
+logos of any Contributor (except as may be necessary to comply with the notice
+requirements in Section 3.4).
+
+      2.4. Subsequent Licenses
+
+No Contributor makes additional grants as a result of Your choice to distribute
+the Covered Software under a subsequent version of this License (see Section
+10.2) or under the terms of a Secondary License (if permitted under the terms
+of Section 3.3).
+
+      2.5. Representation
+
+Each Contributor represents that the Contributor believes its Contributions
+are its original creation(s) or it has sufficient rights to grant the rights
+to its Contributions conveyed by this License.
+
+      2.6. Fair Use
+
+This License is not intended to limit any rights You have under applicable
+copyright doctrines of fair use, fair dealing, or other equivalents.
+
+      2.7. Conditions
+
+Sections 3.1, 3.2, 3.3, and 3.4 are conditions of the licenses granted in
+Section 2.1.
+
+   3. Responsibilities
+
+      3.1. Distribution of Source Form
+
+All distribution of Covered Software in Source Code Form, including any Modifications
+that You create or to which You contribute, must be under the terms of this
+License. You must inform recipients that the Source Code Form of the Covered
+Software is governed by the terms of this License, and how they can obtain
+a copy of this License. You may not attempt to alter or restrict the recipients'
+rights in the Source Code Form.
+
+      3.2. Distribution of Executable Form
+
+      If You distribute Covered Software in Executable Form then:
+
+(a) such Covered Software must also be made available in Source Code Form,
+as described in Section 3.1, and You must inform recipients of the Executable
+Form how they can obtain a copy of such Source Code Form by reasonable means
+in a timely manner, at a charge no more than the cost of distribution to the
+recipient; and
+
+(b) You may distribute such Executable Form under the terms of this License,
+or sublicense it under different terms, provided that the license for the
+Executable Form does not attempt to limit or alter the recipients' rights
+in the Source Code Form under this License.
+
+      3.3. Distribution of a Larger Work
+
+You may create and distribute a Larger Work under terms of Your choice, provided
+that You also comply with the requirements of this License for the Covered
+Software. If the Larger Work is a combination of Covered Software with a work
+governed by one or more Secondary Licenses, and the Covered Software is not
+Incompatible With Secondary Licenses, this License permits You to additionally
+distribute such Covered Software under the terms of such Secondary License(s),
+so that the recipient of the Larger Work may, at their option, further distribute
+the Covered Software under the terms of either this License or such Secondary
+License(s).
+
+      3.4. Notices
+
+You may not remove or alter the substance of any license notices (including
+copyright notices, patent notices, disclaimers of warranty, or limitations
+of liability) contained within the Source Code Form of the Covered Software,
+except that You may alter any license notices to the extent required to remedy
+known factual inaccuracies.
+
+      3.5. Application of Additional Terms
+
+You may choose to offer, and to charge a fee for, warranty, support, indemnity
+or liability obligations to one or more recipients of Covered Software. However,
+You may do so only on Your own behalf, and not on behalf of any Contributor.
+You must make it absolutely clear that any such warranty, support, indemnity,
+or liability obligation is offered by You alone, and You hereby agree to indemnify
+every Contributor for any liability incurred by such Contributor as a result
+of warranty, support, indemnity or liability terms You offer. You may include
+additional disclaimers of warranty and limitations of liability specific to
+any jurisdiction.
+
+   4. Inability to Comply Due to Statute or Regulation
+
+If it is impossible for You to comply with any of the terms of this License
+with respect to some or all of the Covered Software due to statute, judicial
+order, or regulation then You must: (a) comply with the terms of this License
+to the maximum extent possible; and (b) describe the limitations and the code
+they affect. Such description must be placed in a text file included with
+all distributions of the Covered Software under this License. Except to the
+extent prohibited by statute or regulation, such description must be sufficiently
+detailed for a recipient of ordinary skill to be able to understand it.
+
+   5. Termination
+
+5.1. The rights granted under this License will terminate automatically if
+You fail to comply with any of its terms. However, if You become compliant,
+then the rights granted under this License from a particular Contributor are
+reinstated (a) provisionally, unless and until such Contributor explicitly
+and finally terminates Your grants, and (b) on an ongoing basis, if such Contributor
+fails to notify You of the non-compliance by some reasonable means prior to
+60 days after You have come back into compliance. Moreover, Your grants from
+a particular Contributor are reinstated on an ongoing basis if such Contributor
+notifies You of the non-compliance by some reasonable means, this is the first
+time You have received notice of non-compliance with this License from such
+Contributor, and You become compliant prior to 30 days after Your receipt
+of the notice.
+
+5.2. If You initiate litigation against any entity by asserting a patent infringement
+claim (excluding declaratory judgment actions, counter-claims, and cross-claims)
+alleging that a Contributor Version directly or indirectly infringes any patent,
+then the rights granted to You by any and all Contributors for the Covered
+Software under Section 2.1 of this License shall terminate.
+
+5.3. In the event of termination under Sections 5.1 or 5.2 above, all end
+user license agreements (excluding distributors and resellers) which have
+been validly granted by You or Your distributors under this License prior
+to termination shall survive termination.
+
+   6. Disclaimer of Warranty
+
+Covered Software is provided under this License on an "as is" basis, without
+warranty of any kind, either expressed, implied, or statutory, including,
+without limitation, warranties that the Covered Software is free of defects,
+merchantable, fit for a particular purpose or non-infringing. The entire risk
+as to the quality and performance of the Covered Software is with You. Should
+any Covered Software prove defective in any respect, You (not any Contributor)
+assume the cost of any necessary servicing, repair, or correction. This disclaimer
+of warranty constitutes an essential part of this License. No use of any Covered
+Software is authorized under this License except under this disclaimer.
+
+   7. Limitation of Liability
+
+Under no circumstances and under no legal theory, whether tort (including
+negligence), contract, or otherwise, shall any Contributor, or anyone who
+distributes Covered Software as permitted above, be liable to You for any
+direct, indirect, special, incidental, or consequential damages of any character
+including, without limitation, damages for lost profits, loss of goodwill,
+work stoppage, computer failure or malfunction, or any and all other commercial
+damages or losses, even if such party shall have been informed of the possibility
+of such damages. This limitation of liability shall not apply to liability
+for death or personal injury resulting from such party's negligence to the
+extent applicable law prohibits such limitation. Some jurisdictions do not
+allow the exclusion or limitation of incidental or consequential damages,
+so this exclusion and limitation may not apply to You.
+
+   8. Litigation
+
+Any litigation relating to this License may be brought only in the courts
+of a jurisdiction where the defendant maintains its principal place of business
+and such litigation shall be governed by laws of that jurisdiction, without
+reference to its conflict-of-law provisions. Nothing in this Section shall
+prevent a party's ability to bring cross-claims or counter-claims.
+
+   9. Miscellaneous
+
+This License represents the complete agreement concerning the subject matter
+hereof. If any provision of this License is held to be unenforceable, such
+provision shall be reformed only to the extent necessary to make it enforceable.
+Any law or regulation which provides that the language of a contract shall
+be construed against the drafter shall not be used to construe this License
+against a Contributor.
+
+   10. Versions of the License
+
+      10.1. New Versions
+
+Mozilla Foundation is the license steward. Except as provided in Section 10.3,
+no one other than the license steward has the right to modify or publish new
+versions of this License. Each version will be given a distinguishing version
+number.
+
+      10.2. Effect of New Versions
+
+You may distribute the Covered Software under the terms of the version of
+the License under which You originally received the Covered Software, or under
+the terms of any subsequent version published by the license steward.
+
+      10.3. Modified Versions
+
+If you create software not governed by this License, and you want to create
+a new license for such software, you may create and use a modified version
+of this License if you rename the license and remove any references to the
+name of the license steward (except to note that such modified license differs
+from this License).
+
+10.4. Distributing Source Code Form that is Incompatible With Secondary Licenses
+
+If You choose to distribute Source Code Form that is Incompatible With Secondary
+Licenses under the terms of this version of the License, the notice described
+in Exhibit B of this License must be attached. Exhibit A - Source Code Form
+License Notice
+
+This Source Code Form is subject to the terms of the Mozilla Public License,
+v. 2.0. If a copy of the MPL was not distributed with this file, You can obtain
+one at http://mozilla.org/MPL/2.0/.
+
+If it is not possible or desirable to put the notice in a particular file,
+then You may include the notice in a location (such as a LICENSE file in a
+relevant directory) where a recipient would be likely to look for such a notice.
+
+You may add additional accurate notices of copyright ownership.
+
+Exhibit B - "Incompatible With Secondary Licenses" Notice
+
+This Source Code Form is "Incompatible With Secondary Licenses", as defined
+by the Mozilla Public License, v. 2.0.
diff --git a/README.lhs b/README.lhs
--- a/README.lhs
+++ b/README.lhs
@@ -1,3 +1,9 @@
+<!--
+SPDX-FileCopyrightText: 2019 Serokell <https://serokell.io>
+
+SPDX-License-Identifier: MPL-2.0
+-->
+
 # O'Clock
 
 [![Hackage](https://img.shields.io/hackage/v/o-clock.svg)](https://hackage.haskell.org/package/o-clock)
@@ -54,11 +60,9 @@
    * It means that if you want to roll out your own time units and use it in your project,
      this can be done in easy and convenient way (see tutorial below).
 
-6. `O'Clock` contains useful instances like `Hashable`, `NFData`, `Serialise`, `ToJSON`, `FromJSON`
-   but it's not included to the package by default. To do that you need to provide corresponding
-   flag from this list: `hashable`, `deepseq`, `serialise` and `aeson`.
-
-_**Note:**_ features support for `GHC-8.2.2` and `GHC-8.0.2` is quite limited.
+6. `O'Clock` contains useful instances: `ToJSON` and `FromJSON`.
+   However, they are not included to the package by default.
+   To do that, you need to provide the corresponding flag: `aeson`.
 
 ## Example: How to make your own time unit
 
diff --git a/README.md b/README.md
--- a/README.md
+++ b/README.md
@@ -1,3 +1,9 @@
+<!--
+SPDX-FileCopyrightText: 2019 Serokell <https://serokell.io>
+
+SPDX-License-Identifier: MPL-2.0
+-->
+
 # O'Clock
 
 [![Hackage](https://img.shields.io/hackage/v/o-clock.svg)](https://hackage.haskell.org/package/o-clock)
@@ -54,11 +60,9 @@
    * It means that if you want to roll out your own time units and use it in your project,
      this can be done in easy and convenient way (see tutorial below).
 
-6. `O'Clock` contains useful instances like `Hashable`, `NFData`, `Serialise`, `ToJSON`, `FromJSON`
-   but it's not included to the package by default. To do that you need to provide corresponding
-   flag from this list: `hashable`, `deepseq`, `serialise` and `aeson`.
-
-_**Note:**_ features support for `GHC-8.2.2` and `GHC-8.0.2` is quite limited.
+6. `O'Clock` contains useful instances: `ToJSON` and `FromJSON`.
+   However, they are not included to the package by default.
+   To do that, you need to provide the corresponding flag: `aeson`.
 
 ## Example: How to make your own time unit
 
diff --git a/benchmark/Main.hs b/benchmark/Main.hs
--- a/benchmark/Main.hs
+++ b/benchmark/Main.hs
@@ -1,3 +1,7 @@
+-- SPDX-FileCopyrightText: 2020 Serokell <https://serokell.io>
+--
+-- SPDX-License-Identifier: MPL-2.0
+
 {-# OPTIONS_GHC -fno-warn-orphans #-}
 
 {-# LANGUAGE CPP                        #-}
@@ -9,24 +13,17 @@
 
 module Main where
 
-#ifdef NO_deepseq
 import Control.DeepSeq (NFData)
-#endif
 import Gauge (bench, bgroup, defaultMain, nf, whnf)
 
-#ifdef NO_deepseq
-import Time (Rat, Time)
-#endif
-import Time (Day, Hour, Microsecond, Nanosecond, Second, hour, mcs, ns, sec, toUnit, week)
+import Time (Day, Hour, Microsecond, Nanosecond, Rat, Second, Time, hour, mcs, ns, sec, toUnit,
+             week)
 
 import qualified Data.Time.Units as TU (Day, Hour, Microsecond, Nanosecond, Second, Week,
                                         convertUnit)
 import qualified Tiempo (hours, microSeconds, toHours, toMicroSeconds)
 
-
-#ifdef NO_deepseq
 instance NFData (Time (unit :: Rat))
-#endif
 
 main :: IO ()
 main = defaultMain
diff --git a/examples/Playground.hs b/examples/Playground.hs
--- a/examples/Playground.hs
+++ b/examples/Playground.hs
@@ -1,3 +1,7 @@
+-- SPDX-FileCopyrightText: 2019 Serokell <https://serokell.io>
+--
+-- SPDX-License-Identifier: MPL-2.0
+
 {-# LANGUAGE ScopedTypeVariables #-}
 
 module Main where
diff --git a/o-clock.cabal b/o-clock.cabal
--- a/o-clock.cabal
+++ b/o-clock.cabal
@@ -1,14 +1,18 @@
+-- SPDX-FileCopyrightText: 2020 Serokell <https://serokell.io>
+--
+-- SPDX-License-Identifier: MPL-2.0
+
 name:                o-clock
-version:             1.1.0
+version:             1.2.0
 synopsis:            Type-safe time library.
 description:         See README.md for details.
 homepage:            https://github.com/serokell/o-clock
 bug-reports:         https://github.com/serokell/o-clock/issues
-license:             MIT
+license:             MPL-2.0
 license-file:        LICENSE
 author:              @serokell
 maintainer:          Serokell <hi@serokell.io>
-copyright:           2018 Serokell
+copyright:           2020 Serokell
 category:            Time
 build-type:          Simple
 stability:           stable
@@ -16,11 +20,9 @@
                    , README.md
                    , README.lhs
 cabal-version:       2.0
-tested-with:         GHC == 8.4.3
-                   , GHC == 8.4.4
-                   , GHC == 8.6.1
-                   , GHC == 8.6.5
-                   , GHC == 8.8.1
+tested-with:         GHC == 8.6.5
+                   , GHC == 8.8.3
+                   , GHC == 8.10.1
 
 source-repository head
   type:     git
@@ -35,7 +37,7 @@
                          Time.Units
   ghc-options:         -Wall
   build-depends:       base         >= 4.9  && < 5
-                     , ghc-prim     ^>= 0.5
+                     , ghc-prim     >= 0.5 && < 0.7
   default-language:    Haskell2010
   default-extensions:  OverloadedStrings
                        RecordWildCards
@@ -43,18 +45,9 @@
                        TypeApplications
                        TypeFamilies
   if flag(aeson)
-    build-depends:     aeson    >= 1.2.4 && < 1.5
+    build-depends:     aeson    >= 1.2.4 && < 1.6
                      , text
     cpp-options:       -DHAS_aeson
-  if flag(hashable)
-    build-depends:     hashable >= 1.2.6 && < 1.4
-    cpp-options:       -DHAS_hashable
-  if flag(deepseq)
-    build-depends:     deepseq  ^>= 1.4
-    cpp-options:       -DHAS_deepseq
-  if flag(serialise)
-    build-depends:     serialise >= 0.2 && < 0.3
-    cpp-options:       -DHAS_serialise
 
 executable play-o-clock
   main-is:             Playground.hs
@@ -89,6 +82,9 @@
                        RecordWildCards
 
 test-suite o-clock-doctest
+  if os(windows)
+     buildable: False
+
   type:                exitcode-stdio-1.0
   hs-source-dirs:      test
   main-is:             Doctest.hs
@@ -101,6 +97,9 @@
   default-language:    Haskell2010
 
 test-suite readme-test
+  if os(windows)
+     buildable: False
+
   type:                exitcode-stdio-1.0
   main-is:             README.lhs
 
@@ -118,14 +117,11 @@
   hs-source-dirs:      benchmark
   main-is:             Main.hs
   build-depends:       base       >= 4.8   && < 5
+                     , deepseq    >= 1.4
                      , o-clock
                      , gauge      >= 0.2.1 && < 1
                      , tiempo     >= 0.0.1.1
                      , time-units == 1.0.0
-  if !flag(deepseq)
-    build-depends:     deepseq    >= 1.4
-    cpp-options:       -DNO_deepseq
-
   if !flag(bench-buildable)
     buildable:         False
 
@@ -136,18 +132,6 @@
 
 flag aeson
   description:         Provide instances for @aeson@
-  default:             False
-
-flag hashable
-  description:         Provide instances for @hashable@
-  default:             False
-
-flag deepseq
-  description:         Provide instances for @deepseq@
-  default:             False
-
-flag serialise
-  description:         Provide instances for @serialise@
   default:             False
 
 flag bench-buildable
diff --git a/src/Time.hs b/src/Time.hs
--- a/src/Time.hs
+++ b/src/Time.hs
@@ -1,3 +1,7 @@
+-- SPDX-FileCopyrightText: 2019 Serokell <https://serokell.io>
+--
+-- SPDX-License-Identifier: MPL-2.0
+
 -- | This module reexports main functionality.
 --
 -- More information about @O'Clock@ features
diff --git a/src/Time/Rational.hs b/src/Time/Rational.hs
--- a/src/Time/Rational.hs
+++ b/src/Time/Rational.hs
@@ -1,3 +1,7 @@
+-- SPDX-FileCopyrightText: 2019 Serokell <https://serokell.io>
+--
+-- SPDX-License-Identifier: MPL-2.0
+
 {-# LANGUAGE AllowAmbiguousTypes  #-}
 {-# LANGUAGE ConstraintKinds      #-}
 {-# LANGUAGE CPP                  #-}
diff --git a/src/Time/Series.hs b/src/Time/Series.hs
--- a/src/Time/Series.hs
+++ b/src/Time/Series.hs
@@ -1,3 +1,7 @@
+-- SPDX-FileCopyrightText: 2019 Serokell <https://serokell.io>
+--
+-- SPDX-License-Identifier: MPL-2.0
+
 {-# LANGUAGE AllowAmbiguousTypes  #-}
 {-# LANGUAGE CPP                  #-}
 {-# LANGUAGE DataKinds            #-}
@@ -24,7 +28,6 @@
 
 import Data.Char (isDigit, isLetter)
 import Data.Kind (Constraint)
-import Data.Semigroup ((<>))
 import Data.Type.Bool (type (&&), If)
 import Data.Type.Equality (type (==))
 import GHC.TypeLits (ErrorMessage (Text), TypeError)
diff --git a/src/Time/Timestamp.hs b/src/Time/Timestamp.hs
--- a/src/Time/Timestamp.hs
+++ b/src/Time/Timestamp.hs
@@ -1,3 +1,7 @@
+-- SPDX-FileCopyrightText: 2019 Serokell <https://serokell.io>
+--
+-- SPDX-License-Identifier: MPL-2.0
+
 {-# LANGUAGE DataKinds                  #-}
 {-# LANGUAGE ExplicitForAll             #-}
 {-# LANGUAGE FlexibleContexts           #-}
diff --git a/src/Time/Units.hs b/src/Time/Units.hs
--- a/src/Time/Units.hs
+++ b/src/Time/Units.hs
@@ -1,3 +1,7 @@
+-- SPDX-FileCopyrightText: 2019 Serokell <https://serokell.io>
+--
+-- SPDX-License-Identifier: MPL-2.0
+
 {-# LANGUAGE AllowAmbiguousTypes        #-}
 {-# LANGUAGE ConstraintKinds            #-}
 {-# LANGUAGE CPP                        #-}
@@ -62,7 +66,6 @@
        , timeout
        ) where
 
-import Control.Applicative ((*>))
 import Control.Monad (unless)
 import Control.Monad.IO.Class (MonadIO, liftIO)
 import Data.Char (isDigit, isLetter)
@@ -78,18 +81,6 @@
 import Text.ParserCombinators.ReadP (ReadP, char, munch1, option, pfail, (+++))
 import Text.ParserCombinators.ReadPrec (ReadPrec, lift)
 
-#ifdef HAS_hashable
-import Data.Hashable (Hashable)
-#endif
-
-#ifdef HAS_deepseq
-import Control.DeepSeq (NFData)
-#endif
-
-#ifdef HAS_serialise
-import Codec.Serialise (Serialise (..))
-#endif
-
 #ifdef HAS_aeson
 import Data.Aeson (ToJSON (..), FromJSON (..), withText)
 import Text.Read (readMaybe)
@@ -142,18 +133,6 @@
     {-# INLINE mappend #-}
     mconcat = foldl' (<>) mempty
     {-# INLINE mconcat #-}
-
-#ifdef HAS_hashable
-instance Hashable (Time (rat :: Rat))
-#endif
-
-#ifdef HAS_deepseq
-instance NFData (Time (rat :: Rat))
-#endif
-
-#ifdef HAS_serialise
-instance Serialise (Time (rat :: Rat))
-#endif
 
 #ifdef HAS_aeson
 instance (KnownUnitName unit) => ToJSON (Time (unit :: Rat)) where
diff --git a/test/Doctest.hs b/test/Doctest.hs
--- a/test/Doctest.hs
+++ b/test/Doctest.hs
@@ -1,3 +1,7 @@
+-- SPDX-FileCopyrightText: 2019 Serokell <https://serokell.io>
+--
+-- SPDX-License-Identifier: MPL-2.0
+
 module Main (main) where
 
 import System.FilePath.Glob (glob)
diff --git a/test/Spec.hs b/test/Spec.hs
--- a/test/Spec.hs
+++ b/test/Spec.hs
@@ -1,3 +1,7 @@
+-- SPDX-FileCopyrightText: 2019 Serokell <https://serokell.io>
+--
+-- SPDX-License-Identifier: MPL-2.0
+
 module Main where
 
 import Test.Tasty (defaultMain, testGroup)
@@ -12,8 +16,8 @@
     -- type specs
     runTypeSpecTests
     -- Units tests with tasty:
-    -- * toUnit tests
-    -- * read tests
+    -- • toUnit tests
+    -- • read tests
     unitTests <- unitsTestTree
     -- Timestamp tests
     tsTests   <- timeStampTestTree
diff --git a/test/Test/Time/Property.hs b/test/Test/Time/Property.hs
--- a/test/Test/Time/Property.hs
+++ b/test/Test/Time/Property.hs
@@ -1,3 +1,7 @@
+-- SPDX-FileCopyrightText: 2019 Serokell <https://serokell.io>
+--
+-- SPDX-License-Identifier: MPL-2.0
+
 {-# LANGUAGE CPP                 #-}
 {-# LANGUAGE DataKinds           #-}
 {-# LANGUAGE ExplicitForAll      #-}
diff --git a/test/Test/Time/Timestamp.hs b/test/Test/Time/Timestamp.hs
--- a/test/Test/Time/Timestamp.hs
+++ b/test/Test/Time/Timestamp.hs
@@ -1,3 +1,7 @@
+-- SPDX-FileCopyrightText: 2019 Serokell <https://serokell.io>
+--
+-- SPDX-License-Identifier: MPL-2.0
+
 {-# LANGUAGE DataKinds          #-}
 {-# LANGUAGE ExplicitNamespaces #-}
 {-# LANGUAGE TypeApplications   #-}
diff --git a/test/Test/Time/TypeSpec.hs b/test/Test/Time/TypeSpec.hs
--- a/test/Test/Time/TypeSpec.hs
+++ b/test/Test/Time/TypeSpec.hs
@@ -1,3 +1,7 @@
+-- SPDX-FileCopyrightText: 2019 Serokell <https://serokell.io>
+--
+-- SPDX-License-Identifier: MPL-2.0
+
 {-# LANGUAGE CPP           #-}
 {-# LANGUAGE DataKinds     #-}
 {-# LANGUAGE TypeOperators #-}
diff --git a/test/Test/Time/Units.hs b/test/Test/Time/Units.hs
--- a/test/Test/Time/Units.hs
+++ b/test/Test/Time/Units.hs
@@ -1,3 +1,7 @@
+-- SPDX-FileCopyrightText: 2019 Serokell <https://serokell.io>
+--
+-- SPDX-License-Identifier: MPL-2.0
+
 {-# LANGUAGE DataKinds          #-}
 {-# LANGUAGE ExplicitNamespaces #-}
 {-# LANGUAGE TypeApplications   #-}
