On 28 September (Swedish calendar) 1708 a detachment from Lybecker's army fought some sort of engagement near the fortress Koporye. The known Swedish sources seem to be quite few - an official description sent by Lybecker to Governor General Stromberg in Reval, an account by Col. Ramsay who commanded the Swedish force (apparently it's very siimilar to the official one) and a brief note in cavalry captain Bengt Stigman's description of his military career.
Apparently the official account states that the Swedish force consisted of 1,800 horse (Stigman claims 1,500). According to Stigman the Russians were 5,000. Fredrik Hjelmqvist states that Russian prisoners who were captured during the fight claimed there were 3,800 men (5 regiments of dragoons and 1 regiment of Cossacks). The Swedish losses were supposedly 70 men. During the fight the Swedes supposedly managed to capture some letters, among them:
Letters from Vice Admiral Cruys to Brigadier Fraser, dated 19 and 22 September; Letter from Major Blandau to his stepfather Brigadier Fraser, dated 20 September; Letter from Fraser to Major General Bruce, dated 23 September and letter from Bruce to Fraser, dated 24 September.
The sources for this encounter appear to be few in the archive of the Livonian Governor General. The volume containing letters from Cronhjort and Lybecker appears to have been plundered. In LVVA, fond 7349, op. 1, vol. 304 there is a letter from Vyborg dated 9 October, which mentions a vague rumour about a fight near Koporye. Governor General Stromberg writes a few days later (12 October) to Major General von Funcken in Riga. In this letter Stromberg tells Funcken that his scouts (or spies) have returned with news about a fight near Koporye in which the Russians had been soundly beaten. Later, Stromberg continues, Lybecker's army had reached Ivangorod and caused panic among the Russians forces west of Narva. Unfortunately no report had yet arrived from Lybecker, but reports of a fight was coming in from many sources so that part was undoubtedly true (LVVA, fond 7349, op. 1, vol. 332)
In the so called Malmberg papers (rearranged after I used them, so the old volume numbers are useless) in Uppsala there are a few more bits and pieces. The first one is a letter from Lybecker to Major General Funcken, dated 1 October (it did not reach Riga until the 31st). In it Lybecker states that the enemy attempted to take up a strong position near Koporye, but was driven off by a detachment of cavalry. The letter was accompanied by an account of the event, but this attachment is now missing (possibly because it was forwarded elsewhere).
As for the decision to abort the Ingrian campaign the Malmberg papers contributes to items. The first one is a letter from Lybecker, dated 27 October. In this he explains that the supply situation had been difficult, not least because of the continuing rain which had destroyed the roads. The plan to evacuate the army by sea had unfortunately been betrayed by an officer who deserted, so about 400 men were still ashore when the enemy attacked. On 16 November Lybecker again wrote to v. Funcken, further explaining his decision to abort the campaign. This was because of the "barbaric" enemy, who had burnt everything. However, the army had before then handed the Russians several defeats and forced them to bring reinforcements to Ingria. The destruction of the countryside and the losses suffered by the Russians would, Lybecker suggested, make any offensive operations unlikely.
Sources (apart from those specified above):
Hjelmqvist, Fredrik: Kriget i Finland och Ingermanland 1707 och 1708. - Lund, 1909
Karolinska officerares tjänsteförteckningar. - Stockholm, 1901 (Bengt Stigman's "CV", dated 1721)