The list of main improvements made from the first release of SpeCLED &
RATRO 2008 can be found in the HystoryNotes (attached).

Particularly, I would like to emphasize development of RATRO. Now it can
handle substrate sidewalls as well as blocking and spreading layers. Along
with possibility to add a layer with user-defined (n,k) in "multilayer"
cover, the updated RATRO is very flexible in setting ray tracing conditions
for each of chip surface.

Also, we have updated SpeCLED solver window. It provides more clear
visualization of the solution process. Also, a new control parameter, u
residual, has been brought to the user. Each stage of current spreading
solution at fixed voltage stops when both condition are fulfilled:

- Current variation is lower than the specified limit.
- Potential residual (u-residual) is lower than the limit. Note, different
limits can be used for initial stages (seeking for the right voltage) and
for final stage called "Refining solution" in the 'Log' tab.

All other parameters are the same. In the section related to the active
region non-linear conductivity, we have explicitly shown the method used for
linearization.

With default settings new solver operates exactly like the old one (
with exception of some errors that caused crash of the old version).

The default values of "U residual" (1e-6 for initial stage and 1e-8 for
final stage) seem to be a little bit too strict. Sometimes solution is
converged (i.e. current variation is very small, say 1-e8, and solution does
not change), but U residual is still higher than 1e-6. In such situations,
you can increase "U residual" in the solver window (do not forget then press
"Update" button) and get the solution. However, in some of our tests the
current variation becomes low, while the potnetial still shows some
unphysical features. That is why the default values of "U residual" are
strict.
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For your reference, please find below a list of small improvements of GUI
that are not shown in HistoryNotes.

- In 'Material' tab, we changed some text to clarify that all options except
to the "function" deal with temperature dependence. Also, we have
re-designed section describing ITO properties to add some explanation here.

- In 'Run' section, heat transfer boundary conditions are made invisible in
isothermal mode. Also, default values are changed from 5e3 to1e5.
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