The download contains, mainly bugfixes, I managed to load a save made with the 1.6.0 release, and had no issues, much to my surprise...
However,
I strongly recommend to start a new save, considering Nexerelin's release, also meanwhile loading an older save might work, you won't benefit from all bugfixes, specially the doubled ruins bugs.
As an added feature, the retrofit market available conversion data is presented in a new better, IMHO, way. This leaves me with a considerable amount of extra space to add more conversions at a later date, also expanded a bit the list of available conversions to include more non-updated yet mods. The lists will change according the mods you have installed.
Additionally added "IPC" variant skins of many high tech ships, to get them you'll need to unlock the retrofitting market, convert one of the listed ships, and wait until it is done. Keep in mind that the market only accepts ships with no Dmods, so you might need to restore them before converting them. The "IPC", named as such for the "Integrated Particle Conduits" hullmod, adds that hullmod to the ship, and the effect weapon required for the "Fleet Server" hullmod, it also adds all the negatives of having the IPC hullmod.
At the moment the IPC conversion includes almost all vanilla phase ships (gremlin excluded). Converting a phase ship, however, might not be the best idea at the moment, since they can't mount "Shielded Plating", partly benefit from "Sand Caster", leaving only "Graviton Lensing" with its full effect, and beam weapons are not usually what you would mount on them; they do benefit from "Fleet Server" though, although I'm not sure if that is helpful.
I do plan to add some IPC hullmods that benefit phase ships at a later date though.
As something of note, the conversion market should work for ships added my mods, and since its list is no longer autogenerated, some ships that would have been listed separately, have been grouped. As an example, a wolf variant skin added by some mod, that wasn't actually a skin file, but a different ship (like my own TSC wolf), would be considered as already added in the "reconstruction list", when before it might have appeared as a doubled entry in the list.
There is a vanilla bug, which I mentioned previously, where illegal transfer texts, won't work on "storage markets" for ships, meanwhile this bug has already been notified, it might explain why some ships that might appear as conversion able, aren't. At the moment the TSC will refuse converting Cabal ships (there's no real reason why, but as I picture it, lorewise, the TSC might be worried of potential "troyans" built-into Cabal ships), and also ships with Dmods, need to be restored properly before converting.
Anyway, if I missed some mod-added ship, or you think I should add a specific conversion, just post a comment, changing the part that handles the conversion list of the market script is fully save compatible.
"Full changelog" in the section below.
New Retrofitting Market
Spoiler
Unmodded (mostly, just the bare basics, and my mod)

Heavily modded (almost all mods available, and some that aren't, sadly not many changes yet, since most fall into already existing lists)

Changelog:
Version 1.6.1:
Spoiler
-Nexerelin compatibility changes.
-Improved the tooltip of Arcon's retrofitting submarket.
-Added IPC (Integrated Particle Conduits) "skins" (technically, they still use the same sprite) to some high tech ships, this allows them to mount the IPC dependant hullmods and fleet server.
-Added the ability to transform some vanilla ships into their IPC skins, via the retrofitting submarket at Arcon.
-Fixed a potential gamecrash issues related to a pair of ship skins with a pre-applied D-overlay.
-Fixed linux gamecrash related to case sensitivity.
-Fixed a gamecrash issue when refitting the ship skins of ships with modules.
-Removed modules from all ships that had a Ram Drive shipsystem; the shipsystem no longer depends on it. Can't do the same for Burst shield though.
-Adarga (P), is no longer a skin of the Adarga, this won't be apparent to the player, but is part of the gamecrash bugfix.
-Replaced Vanguard Halberd shipsystem with fortress shield, a sad consequence of the bugfix.
-Removed all Dmods from pirate skins, with the exception Damaged Particle Conduits.
-Fixed doubled ruins planetary conditions bug from appearing in procgen planets.
-Reduced drop chance of TSC individual ship, fighter and weapons blueprints. This also increased very slightly the drop chance of the TSC blueprints packages.
-Reduced the beam width of the Strategic Laser and removed its flare effect, to make it more visually consistent with its power.
-Balance Changes:
-Halberd (Vanguard)-class Battleship:
-Replaced "Shield Burst" shipsystem with "Fortress Shields".
-Medusa (D)-class Destroyer:
-Removed blueprint tags, was wrongly added to the pirate tag.
-Ram Drive shipsystem:
-No longer requires a module to work.
-Shield activation happens very slightly later, about 0.5 seconds.
-Shield remains on after the system finishes.
-Since the system uses now the ship's own shield, AoE damage shield bleed through should followe the same exact rules as with shields.
-Dedicated Launch Bays hullmod:
-Made incompatible with phase ships from the "Shadowyards" mod.
-Integrated Particle Conduits hullmod:
-Made incompatible with "Shield Bypass" hullmod from "Ship and Weapon Pack" mod.
-Shielded Plating hullmod:
-Made incompatible with ships without shields.