diff --git a/HISTORY.md b/HISTORY.md
index 1d8c6ea..958267a 100644
--- a/HISTORY.md
+++ b/HISTORY.md
@@ -2,6 +2,27 @@
 
 ## v1.1.8
 
+Another minor update to address issues arising from running with GEOS IT.
+
+1. Download URLs for GEOS IT updated to latest product.
+2. Solves an issue running the satellite interface (`oco`, `gosat`, or `geocarb` subcommands)
+   with 3 GEOS IT input. The interpolators created for the GEOS IT files are large enough that
+   three cannot be passed between threads in Python 3.6 due to a limit on the number of bytes
+   that the Python 3.6 multiprocessing module can pickle. This is fixed by Python 3.10 at the
+   latest, but getting Python 3.10 and required numerical dependencies to reproduce the Python
+   3.6 results to numerical precision was not possible. Therefore, as a workaround, if the 
+   satellite interface detects that it is running on Python 3.9 or earlier, it will pickle the
+   interpolators as separate files and load them back in from the threads when `--nprocs` is not
+   0.
+
+There are two other aspects to this release:
+
+1. This is the first release that can be run on Python 3.10 and has the changes needed to run
+  the satellite interface with GEOS IT files. v1.1.7 didn't have those GEOS IT changes and
+  v1.1.5d was not compatible with Python 3.6.
+2. The unit testing code now ignores the GINPUT_VERSION value in the `.vmr` file headers; this
+  saves us from needing to update the test input files with each version if there should not
+  be changes in the output.
 
 ## v1.1.7
 
diff --git a/ginput/priors/tccon_priors.py b/ginput/priors/tccon_priors.py
index 382e987..f236a9b 100644
--- a/ginput/priors/tccon_priors.py
+++ b/ginput/priors/tccon_priors.py
@@ -2705,8 +2705,10 @@ def calculate_meso_co(alt_profile, eqlat_profile, pres_profile, temp_profile, pr
         co_alts = ds['altitude'][:]
 
     # In the LUT, nair is assumed to be the same for every profile (because pressure is) so we don't need to interpolate
-    # anything before we calculate the effective vertical path we'll use to integrate the CO profiles
-    vpath = mod_utils.effective_vertical_path(co_alts.data, nair=co_nair.data)
+    # anything before we calculate the effective vertical path we'll use to integrate the CO profiles.
+    # Since we only care about the mesosphere, we'll just use zmin = 0 for all calculations (it won't affect anything
+    # except the level about the surface).
+    vpath = mod_utils.effective_vertical_path(co_alts.data, zmin=0.0, nair=co_nair.data)
     plev = co_nd.plev
     prof_doy = mod_utils.day_of_year(prof_date)
     # Unlike the extra strat CO, we don't need the CO on the same levels as any existing profile, we want it on its
@@ -2722,7 +2724,8 @@ def calculate_meso_co(alt_profile, eqlat_profile, pres_profile, temp_profile, pr
     meso_co_col = np.sum(vpath[xx_meso] * 1e5 * cmam_co_prof[xx_meso])
 
     # Now we need the effective vertical path for the top level of the actual CO profile.
-    top_prior_vpath = mod_utils.effective_vertical_path(z=alt_profile, p=pres_profile, t=temp_profile)[-1]
+    # Again, the actual value of zmin does not matter here so we just use 0.
+    top_prior_vpath = mod_utils.effective_vertical_path(z=alt_profile, p=pres_profile, t=temp_profile, zmin=0.0)[-1]
 
     # So we can calculate the number density and then the mixing ratio (convert to ppb) that would result from putting
     # the CO column above the top level into the top level with the effective path length that we calculated and an