diff --git a/bob/bio/base/script/grid_search.py b/bob/bio/base/script/grid_search.py
index 372f78fa8f8d88f245014428a190669bb138726d..12ead1f6c767eb2a0b7d4b9b0d3fbd7412d2ca7c 100755
--- a/bob/bio/base/script/grid_search.py
+++ b/bob/bio/base/script/grid_search.py
@@ -264,6 +264,9 @@ def check_requirements(replacements):
   global configuration
   values = {}
   for key in configuration.replace:
+    # check that the key is one of the known steps
+    if key not in steps:
+      raise ValueError("The step '%s' defined in the configuration file is unknown; choose one of %s" % (key, steps))
     values.update(extract_values(configuration.replace[key], replacements))
   for requirement in configuration.requirements:
     test = replace(requirement, values)
diff --git a/doc/more.rst b/doc/more.rst
index 4141d38aaa0507e7e15677421ec137a4c1ae020f..37c4489f683dec67aa2a29838aa0a4c7e8d19aef 100644
--- a/doc/more.rst
+++ b/doc/more.rst
@@ -74,7 +74,7 @@ The variables 1. to 3. can also be overridden by the command line options ``--pr
 
 The ``replace`` variable has to be set as a dictionary.
 In it, you can define with which values your place holder key should be filled, and in which step of the tool chain execution this should happen.
-The steps are ``'preprocessing'``, ``'extraction'``, ``'projection'``, ``'enrollment'`` and ``'scoring'``.
+The steps are ``'preprocess'``, ``'extract'``, ``'project'``, ``'enroll'`` and ``'score'``.
 For each of the steps, it can be defined, which placeholder should be replaced by which values.
 To be able to differentiate the results later on, each of the replacement values is bound to a directory name.
 The final structure looks somewhat like that:
diff --git a/requirements.txt b/requirements.txt
index 5dd5955e9786fe72a42f1a5fc7be3ba06f81eeea..a9e9258f01f2a42d3fc51909951bcb9304bb6719 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -5,7 +5,7 @@ bob.core
 bob.io.base
 bob.learn.activation
 bob.math
-bob.learn.linear==2.0.6
+bob.learn.linear
 bob.sp
 bob.learn.em
 bob.measure