diff --git a/pyerrors/correlators.py b/pyerrors/correlators.py
index ee949276..41c61985 100644
--- a/pyerrors/correlators.py
+++ b/pyerrors/correlators.py
@@ -274,6 +274,9 @@ class Corr:
             for t in range(self.T - 1):
                 if (self.content[t] is None) or (self.content[t + 1] is None):
                     newcontent.append(None)
+                # Fill the two timeslices in the middle of the lattice with their predecessors
+                elif variant == 'sinh' and t in [self.T / 2, self.T / 2 - 1]:
+                    newcontent.append(newcontent[-1])
                 else:
                     newcontent.append(np.abs(find_root(self.content[t][0] / self.content[t + 1][0], root_function, guess=guess)))
             if(all([x is None for x in newcontent])):
diff --git a/setup.py b/setup.py
index 988c32a2..df32d698 100644
--- a/setup.py
+++ b/setup.py
@@ -9,5 +9,5 @@ setup(name='pyerrors',
       author_email='fabian.joswig@ed.ac.uk',
       packages=find_packages(),
       python_requires='>=3.6.0',
-      install_requires=['numpy>=1.16', 'autograd>=1.2', 'numdifftools', 'matplotlib', 'scipy', 'iminuit<2']
+      install_requires=['numpy>=1.16', 'autograd>=1.2', 'numdifftools', 'matplotlib>=3.3', 'scipy', 'iminuit<2']
      )
diff --git a/tests/test_correlators.py b/tests/test_correlators.py
index 502f26fa..63f1a755 100644
--- a/tests/test_correlators.py
+++ b/tests/test_correlators.py
@@ -49,9 +49,10 @@ def test_modify_correlator():
     corr.second_deriv()
 
 def test_m_eff():
-    my_corr = pe.correlators.Corr([pe.pseudo_Obs(10, 0.1, 't'), pe.pseudo_Obs(9, 0.05, 't')])
+    my_corr = pe.correlators.Corr([pe.pseudo_Obs(10, 0.1, 't'), pe.pseudo_Obs(9, 0.05, 't'), pe.pseudo_Obs(8, 0.1, 't'), pe.pseudo_Obs(7, 0.05, 't')])
     my_corr.m_eff('log')
     my_corr.m_eff('cosh')
+    my_corr.m_eff('sinh')
 
 def test_utility():
     corr_content = []